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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2016	Mar. 07, 2017	Jun. 30, 2016
Document Information [Line Items]
Entity Registrant Name	KEMPHARM, INC
Entity Central Index Key	0001434647
Trading Symbol	kmph
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		14,646,982
Entity Public Float			$ 46,412,563
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Amendment Flag	false

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 16,762	$ 32,318
Restricted cash	1,100
Marketable securities	51,003	19,002
Trade date receivables	5,003
Prepaid expenses and other current assets	489	2,758
Total current assets	74,357	54,078
Property and equipment, net	1,970	403
Long-term investments	8,200
Other long-term assets	360	109
Total assets	84,887	54,590
Liabilities and stockholders’ deficit
Accounts payable and accrued expenses	6,444	4,906
Current portion of convertible notes		1,369
Current portion of term notes		2,041
Current portion of capital lease obligation	157	26
Other current liabilities	41
Total current liabilities	6,642	8,342
Convertible notes, net	91,170	7,412
Term notes, net		11,118
Derivative and warrant liability	4,618	37,839
Other long-term liabilities	1,153
Total liabilities	103,583	64,711
Commitments and contingencies (Note G)
Stockholders' deficit:
Common stock, $0.0001 par value, 250,000,000 shares authorized, 14,646,982 shares issued and outstanding as of December 31, 2016; 14,490,954 shares issued and outstanding as of December 31, 2015	1	1
Additional paid-in capital	102,643	94,702
Preferred stock, $0.0001 par value, 10,000,000 shares authorized, no shares issued or outstanding as of December 31, 2016 or December 31, 2015	0	0
Accumulated deficit	(121,340)	(104,824)
Total stockholders' deficit	(18,696)	(10,121)
Total liabilities and stockholders' deficit	$ 84,887	$ 54,590

Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	14,646,982	14,490,954
Common stock, shares outstanding (in shares)	14,646,982	14,490,954
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Statements of Operations - USD ($) $ in Thousands	12 Months Ended
Statements of Operations - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Operating expenses:
Research and development	20,472	13,931	11,917
General and administrative	14,000	8,883	4,526
Severance expense	3,010
Total operating expenses	37,482	22,814	16,443
Loss from operations	(37,482)	(22,814)	(16,443)
Other income (expense):
(Loss) gain on extinguishment of debt	(4,740)		1,900
Interest expense related to amortization of debt issuance costs and discount	(1,616)	(1,909)	(1,114)
Interest expense on principal	(5,511)	(2,671)	(1,605)
Fair value adjustment	32,465	(27,276)	(7,223)
Interest and other income	353	32	8
Total other income (expense)	20,951	(31,824)	(8,034)
Loss before income taxes	(16,531)	(54,638)	(24,477)
Income tax benefit (expense)	15	(26)	22
Net loss	$ (16,516)	$ (54,664)	$ (24,455)
Net loss per share:
Basic and diluted (in dollars per share)	$ (1.13)	$ (7.42)	$ (10.27)
Weighted average common shares outstanding:
Basic and diluted (in shares)	14,597,053	7,368,681	2,381,041

Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Series A Redeemable Convertible Preferred Stock [Member]	Series B Redeemable Convertible Preferred Stock [Member]	Series C Redeemable Convertible Preferred Stock [Member]	Series D Redeemable Convertible Preferred Stock [Member]	Series D-1 Redeemable Convertible Preferred Stock [Member]	Redeemable Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2013	$ 3,343	$ 3,313	$ 11,892			$ 18,548
Balance at Dec. 31, 2013							$ 1,438		$ (25,705)	$ (24,267)
Net loss									(24,455)	(24,455)
Stock-based compensation expense								$ 214		214
Change in par value							(1,438)	1,438
Conversion of 2013 convertible notes into Series D preferred stock				$ 4,159		4,159
Issuance of Series D preferred stock as financing fee				1,500		1,500
Balance at Dec. 31, 2014	3,343	3,313	11,892	5,659		24,207
Balance at Dec. 31, 2014								1,652	(50,160)	(48,508)
Net loss									(54,664)	(54,664)
Stock-based compensation expense								2,369		2,369
Balance at Dec. 31, 2015							1	94,702	(104,824)	(10,121)
Exercise of stock options and warrants								4,749		4,749
Issuance of Series D-1 preferred stock					$ 4,000	4,000
Issuance of common stock in connection with IPO, net of discounts and commissions							1	59,891		59,892
Conversion of 2013 warrants to equity classification								1,110		1,110
Conversion of preferred stock into common stock upon IPO	$ (3,343)	$ (3,313)	$ (11,892)	$ (5,659)	$ (4,000)	$ (28,207)		28,207		28,207
Offering expenses charged to equity								(3,276)		(3,276)
Net loss									(16,516)	(16,516)
Stock-based compensation expense								6,600		6,600
Balance at Dec. 31, 2016							$ 1	102,643	$ (121,340)	(18,696)
Exercise of stock options and warrants								896		896
Write-off of deferred offering costs								$ 445		$ 445

Statements of Cash Flows - USD ($)	12 Months Ended
Statements of Cash Flows - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (16,516,000)	$ (54,664,000)	$ (24,455,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss (gain) on extinguishment of debt	4,740,000		(1,900,000)
Write-off of deferred offering costs	445,000
Stock-based compensation expense	6,600,000	2,369,000	214,000
Non-cash interest expense	2,222,000	2,671,000	1,602,000
Amortization of debt issuance costs and debt discount	1,616,000	1,909,000	1,114,000
Depreciation and amortization expense	175,000	84,000	75,000
Fair value adjustment	(32,465,000)	27,276,000	7,223,000
Loss on disposal of fixed assets	91,000
Change in assets and liabilities:
Prepaid expenses and other assets	2,018,000	(1,228,000)	523,000
Accounts payable and accrued expenses	1,118,000	1,315,000	933,000
Other long-term liabilities	184,000
Net cash used in operating activities	(29,772,000)	(20,268,000)	(14,671,000)
Cash flows from investing activities:
Purchases of property and equipment	(643,000)	(135,000)	(47,000)
Restricted cash for collateral	(1,100,000)
Purchases of marketable securities and long-term investments	(89,849,000)	(19,002,000)
Maturities of marketable securities and long-term investments	44,645,000
Net cash used in investing activities	(46,947,000)	(19,137,000)	(47,000)
Cash flows from financing activities:
Proceeds from issuance of debt, net of discounts and commissions	82,800,000		25,000,000
Repayment of term notes and related accrued interest	(18,621,000)
Payment of principal on convertible notes arising from capitalized interest	(1,931,000)
Payment of deferred offering costs	(164,000)	(315,000)	(1,767,000)
Payment of debt and stock issuance costs	(983,000)	(2,533,000)	(163,000)
Repayment of obligations under capital lease	(79,000)	(32,000)	(31,000)
Proceeds from exercise of warrants	141,000	413,000
Proceeds from initial public offering, net of discounts and commissions		59,892,000
Repayment of line of credit			(35,000)
Net cash provided by financing activities	61,163,000	61,468,000	23,004,000
Net (decrease) increase in cash and cash equivalents	(15,556,000)	22,063,000	8,286,000
Cash and cash equivalents, beginning of year	32,318,000	10,255,000	1,969,000
Cash and cash equivalents, end of year	16,762,000	32,318,000	10,255,000
Supplemental cash flow information:
Cash paid for interest	3,289,000		3,000
Transfer of warrants to equity upon exercise	755,000	4,293,000
Fixed assets included in accounts payable and accrued expenses	281,000
Deferred offering costs included in accounts payable and accrued expenses	85,000	428,000	315,000
Fixed assets financed under a capital lease agreement	867,000
Trade date receivables	5,003,000
Unpaid offering costs charged to equity		3,276,000
Conversion of preferred stock into common stock upon initial public offering		28,207,000
Reclassification of 2013 warrants to equity		1,110,000
Embedded put option on Deerfield warrant			220,000
Issuance of Series D preferred stock as transaction fee			1,500,000
Conversion of 2013 convertible notes and interest into Series D preferred stock			4,159,000
Issuance of 2013 warrants and Deerfield warrant			7,610,000
Series D-1 Redeemable Convertible Preferred Stock [Member]
Cash flows from financing activities:
Proceeds from issuance of Series D-1 redeemable convertible preferred stock		4,000,000
Series D Redeemable Convertible Preferred Stock [Member]
Cash flows from financing activities:
Proceeds from exercise of warrants		$ 43,000

Note A - Description of Business and Basis of Presentation

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Business Description and Basis of Presentation [Text Block]

A.	Description of Business and Basis of Presentation

KemPharm, Inc. (the “

Company”) is a clinical-stage specialty pharmaceutical company engaged in the discovery and development of proprietary prodrugs. Through the use of its Ligand Activated Therapy (“LAT”) platform technology, the Company is able to initiate and pursue the development of improved versions of widely prescribed, approved drugs. The Company was formed on

October

30,

2006,

and incorporated in Iowa, and reorganized in Delaware on

May

30,

2014.

The Company has experienced recurring losses from

operations and negative operating cash flows due to its ongoing research and development of its potential product candidates. The Company also has an accumulated deficit at

December

31,

2016.

Various internal and external factors will affect whether and when the candidates become approved drugs and how significant their market share will be. The length of time and cost of developing and commercializing these candidates and/or failure of them at any stage of the drug approval process will materially affect the Company’s financial condition and future operations.

Reverse Stock Split

April

2015,

the Company effected a

-for-

7.5

reverse stock split of its issued common stock. All applicable share data, per share amounts and related information in the financial statements and notes thereto have been adjusted re

troactively to give effect to the

-for-

7.5

reverse stock split.

Initial Public Offering

April

2015,

the Company completed an initial public offering (“IPO”) of its common stock. In connection with the initial closing of the IPO, the Company sold an aggregate of

5,090,909

shares of common stock at a price to the public of

$11.00

per share. In

May

2015,

the underwriters in the IPO exercised their option to purchase additional shares pursuant to which the Company sold an additional

763,636

shares of common stock at a price equal to the public price of

$11.00

per share. In the aggregate, net proceeds from the IPO, including net proceeds from the underwriter

s’ exercise of their option to purchase additional shares, were

$59.9

million, after deducting underwriting discounts and commissions of

$4.5

million. In addition, offering expenses totaled

$2.8

million. Upon completion of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock were converted or reclassified into

5,980,564

shares of common stock and all outstanding warrants to acquire shares of the Company’s redeemable convertible preferred stock became warrants to acquire the Company’s common stock. In connection with the IPO, the Company amended and restated its Amended and Restated Certificate of Incorporation to change the authorized capital stock to

250,000,000

shares, designated as common stock, and

10,000,000

shares, designated as preferred stock, each with a par value of

$0.0001

per share.

Entry into

ATM Agreement

October

2016,

the Company entered into a Common Stock Sales Agreement (the “

ATM Agreement”) with Cowen and Company (“Cowen”) under which the Company

may

offer and sell, from time to time, in its sole discretion, shares of common stock having an aggregate offering price of up to

$50,000,000

through Cowen as the Company's sales agent. The registration statement on Form S-

included a prospectus covering the offering up to

$20,000,000

of shares of common stock in accordance with the ATM Agreement.

The Company

’s registration statement on Form S-

contemplated under the ATM Agreement was declared effective by the SEC on

October

17,

2016.

Cowen

may

sell common stock under the

ATM Agreement by any method permitted by law deemed to be an “at the market offering” as defined in Rule

415

of the Securities Act, including without limitation sales made by means of ordinary brokers’ transactions on The NASDAQ Global Market or otherwise at market prices prevailing at the time of sale, in block transactions, or as otherwise directed by the Company. Cowen will use commercially reasonable efforts to sell the common stock from time to time, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions the Company

may

impose). The Company will pay Cowen a commission of up to

three

percent

(3.0%)

of the gross sales proceeds of any common stock sold through Cowen under the ATM Agreement, and also has provided Cowen with customary indemnification rights.

The Company is not obligated to make any sales of common stock under the

ATM Agreement. The offering of shares of common stock pursuant to the ATM Agreement will terminate upon the earlier of (i) the sale of all common stock subject to the ATM Agreement, or (ii) termination of the ATM Agreement in accordance with its terms.

As of

December

31,

2016,

the Company had deferred offering costs recorded within other long-term assets in the amount of

$0.2

million.

Reclas

sifications

During the

first

quarter of

2016

, the Company adopted Accounting Standards Update (“ASU”)

2015

03,

Interest – Imputation of Interest (Subtopic

835

30)

(“ASU

2015

03”),

which requires the debt issuance costs related to a recognized debt liability be presented in the balance sheet as direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts. The adoption of ASU

2015

reduced the Company’s assets and liabilities by the amount of the debt issuance costs, which was

$1.1

million at

December

31,

2015.

This reclassification had no effect on reported net loss or cash flows.

Note B - Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Significant Accounting Policies [Text Block]

B.	Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP")

requires the Company to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

On an ongoing basis, the Company evaluates its estimates, includ

ing those related to the useful lives of property and equipment, and assumptions used for purposes of determining stock-based compensation, income taxes, and the fair value of the derivative and warrant liability, among others. The Company bases its estimates on historical experience and on various other assumptions that it believes to be reasonable, the results of which form the basis for making judgments about the carrying value of assets and liabilities.

Concentration of Credit Risk

Financial instruments that potentially expose

the Company to concentrations of credit risk consist principally of cash on deposit with multiple financial institutions, the balances of which frequently exceed insured limits.

Cash and Cash Equivalents

The Company considers any highly liquid investm

ents with an original maturity of

three

months or less to be cash equivalents.

Marketable Securities and Long-term Investments

The Company maintains investment securities that are classified as trading securities. These securities are carried at fair value with unreali

zed gains and losses included in other income (expense) on the statements of operations. The securities primarily consist of certificates of deposit, U.S. Treasury securities and U.S. government-sponsored agency securities. As of

December

31,

2016

and

2015,

respectively, the Company held marketable securities and long-term investments with an aggregate fair value of

$50.4

million and

$10.1

million that contained aggregate unrealized losses of

$50,000

and

$6,000,

respectively. These marketable securities and long-term investments have been in a continuous unrealized loss position for less than

months and the Company expects these investments to fully recovery prior to their maturity.

Property and Equipment

The Company records property and equipment at cost less accumulated

depreciation and amortization. Costs of renewals and improvements that extend the useful lives of the assets are capitalized. Maintenance and repairs are expensed as incurred. Depreciation is determined on a straight-line basis over the estimated useful lives of the assets, which generally range from

three

fifteen

years. Leasehold improvements are amortized over the shorter of the useful life of the asset or the term of the related lease. Upon retirement or disposition of assets, the costs and related accumulated depreciation and amortization are removed from the accounts with the resulting gains or losses, if any, reflected in results of operations.

Debt Issuance Costs

Debt issuance costs incurred in connection with financing arrangements are amortiz

ed over the life of the respective financing arrangement using the effective interest method.

Supply Arrangements

The Company enters into supply arrangements for the supply of components of its product candidates. These arrangements also

may

include a

share of future revenue if related product candidates reach commercialization. Costs under these supply arrangements, if any, are expensed as incurred (Note H).

Impairment of Long-Lived Assets

Long-lived assets to be held and used are reviewed for

impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets

may

not be recoverable. When such events occur, the Company compares the carrying amounts of the assets to their undiscounted expected future cash flows. If the undiscounted cash flows are insufficient to recover the carrying values, an impairment loss is recorded for the difference between the carrying values and fair values of the asset.

such impairment occurred for the years ended

December

31,

2016,

2015

and

2014.

Fair Value of Financial Instruments

The accounting standard for fair value measurements provides a framework for measuring fair value and requires disclosures regarding fair value measurements. Fair value is defined as the price that would be

received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, based on the Company’s principal or, in absence of a principal, most advantageous market for the specific asset or liability.

The Company uses a

three

-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subs

equent to their initial measurement. The hierarchy requires the Company to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value. The

three

tiers are defined as follows:

●

Level

—Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets;

●

Level

—Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities; and

●

Level

—Unobservable inputs that are supported by little or no market data, which require the Company to develop its own assumptions.

Research and Development

Major components of research and development costs include cash compensation, stock-based compensation, depreciation and amortization expense on research and development property and equipment, costs of preclinical studies, clin

ical trials and related clinical manufacturing, costs of drug development, costs of materials and supplies, facilities cost, overhead costs, regulatory and compliance costs, and fees paid to consultants and other entities that conduct certain research and development activities on the Company’s behalf. Costs incurred in research and development are expensed as incurred.

The Company records nonrefundable advance payments it makes for future research and development activities as prepaid expenses. Prepaid

expenses are recognized as expense in the statements of operations as the Company receives the related goods or services.

Patent Costs

Patent costs, including related legal costs, are expensed as incurred and recorded within general and administrative

expenses on the statements of operations.

Income Taxes

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax basis of assets and liabilities,

as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. Valuation allowances are recorded to reduce deferred tax assets to the amount the Company believes is more likely than not to be realized.

Uncertain tax positions are recognized only when the Company believes it is more likely than not tha

t the tax position will be upheld on examination by the taxing authorities based on the merits of the position. The Company recognizes interest and penalties, if any, related to unrecognized income tax uncertainties in income tax expense. The Company did not have any accrued interest or penalties associated with uncertain tax positions as of

December

31,

2016

and

2015.

The Company files income tax returns in the United States for federal and various state jurisdictions. With few exceptions,

the Company is no longer subject to U.S. federal and state and local income tax examinations for years prior to

2012,

although carryforward attributes that were generated prior to

2012

may

still be adjusted upon examination by the Internal Revenue Service if used in a future period. No income tax returns are currently under examination by taxing authorities.

Stock-Based Compensation

The Company measures and recognizes compensation expense for all stock-based payment awards made to employees, officers an

d directors based on the estimated fair values of the awards as of the grant date. The Company records the value of the portion of the award that is ultimately expected to vest as expense over the requisite service period. The Company also accounts for equity instruments issued to non-employees using a fair value approach under Accounting Standards Codification ("ASC") subtopic

505

50.

The Company values equity instruments and stock options granted using the Black-Scholes option pricing model. The value of non-employee stock-based compensation is subject to periodic adjustments as the underlying equity instruments vest and is recognized as an expense over the term of the related financing or the period over which services are received.

Basic and Diluted Net

Loss per Share of Common Stock

The Company uses the

two

-class method to compute net loss per common share because the Company has issued securities, other than common stock, that contractually

entitle the holders to participate in dividends and earnings of the Company. The

two

-class method requires earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive distributed and undistributed earnings. Holders of each series of the Company’s redeemable convertible preferred stock are entitled to participate in distributions, when and if declared by the board of directors, that are made to common stockholders and, as a result, are considered participating securities.

Segment and Geographic Information

Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is ava

ilable and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker (CODM) is its Chief Executive Officer. The Company views its operations and manages its business as a single operating and reporting segment. All assets of the Company were held in the United States as of

December

31,

2016

and

2015.

Application of New or Revised Accounting Standards

—Adopted

From time to time, the Financial Accounting Standards Board (the “FASB”) or other standard-setting bodies issue accounting standards that are adopted by the Company as of the specified effective date

April

2012,

President Obama signed the Jump-Start Our Business Startups Act (the “

JOBS Act”) into law. The JOBS Act contains provisions that, among other things, reduce certain reporting requirements for an emerging growth company. As an emerging growth company, the Company

may

elect to adopt new or revised accounting standards when they become effective for non-public companies, which typically is later than public companies must adopt the standards. The Company has elected not to take advantage of the extended transition period afforded by the JOBS Act and, as a result, will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for non-emerging growth companies.

June

2014,

the FASB

issued ASU

2014

12,

Compensation–Stock Compensation

(Topic

718):

Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period

(“ASU

2014

12”).

The amendments require that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. ASU

2014

is effective for annual periods and interim periods within those annual periods beginning after

December

15,

2015.

Entities

may

apply ASU

2014

either (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company prospectively adopted ASU

2014

effective

January

2016.

The adoption of ASU

2014

did not have a material impact on the financial statements as the Company does not have any performance-based awards whereby performance could be achieved after the requisite service period.

August

2014,

the FASB issued ASU No.

2014

15,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

(“ASU

2014

15”),

which amends ASC Subtopic

205

to provide guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related disclosures. Specifically, the amendments

(1)

provide a definition of the term “substantial doubt,”

(2)

require an evaluation every reporting period,

(3)

provide principles for considering the mitigating effect of management’s plans,

(4)

require certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans,

(5)

require an express statement and other disclosures when substantial doubt is not alleviated and

(6)

require an assessment for a period of

one

year after the date that financial statements are issued. ASU

2014

is effective for fiscal years ending after

December

15,

2016,

and for annual periods and interim periods thereafter.

The adoption of ASU

2014

did not have a material impact on the Company

’s financial statements as the Company determined there was no substantial doubt about its ability to continue as a going concern as of

December

31,

2016.

January

2015,

the FASB issued ASU No.

2015

01,

Income Statement - Extraordinary and Unusual Items (Subtopic

225

20);

Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU

2015

01”)

, which eliminates from GAAP the concept of extraordinary items, stating that the concept causes uncertainty because

(1)

it is unclear when an item should be considered both unusual and infrequent and

(2)

users do not find the classification and presentation necessary to identify those events and transactions. ASU

2015

is effective for fiscal years, and interim periods within those fiscal years, beginning after

December

15,

2015.

The Company adopted ASU

2015

effective

January

2016.

The adoption of ASU

2015

did not have a material impact on the Company’s financial statements as the Company had no extraordinary and/or unusual items recorded in prior periods.

April

2015,

the FASB issued ASU

2015

03,

which requires the debt issuance costs relate

d to a recognized debt liability be presented in the balance sheet as direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts. This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2015,

and interim periods within those fiscal years. The adoption of ASU

2015

reduced the Company’s assets and liabilities by the amount of the debt issuance costs, which was

$1.1

million at

December

31,

2015.

This reclassification had no effect on reported net loss or cash flows.

Application of New or Revised Accounting Standards

—Not Yet Adopted

May

2014,

the FASB issued guidance codified in ASC Topic

606,

Revenue Recognition—Revenue from Contracts with Customers

("ASC

606"),

which amends the guidance in former ASC

605,

Revenue Recognition

, and becomes effective beginning

January

2018.

The Company does not currently expect this standard to have a material effect on its financial statements upon adoption since the Company is not generating revenue at this time.

November

2015,

the FASB issued ASU

2015

17,

Income Taxes: Balance Sheet Classification of Deferred Taxes (Topic

740)

(“ASU

2015

17”),

which requires that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. This update applies to all entities that present a classified statement of financial position. This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2016,

and interim periods within those fiscal years. The Company does not currently expect this standard to have a material effect on its financial statements and disclosures upon adoption since the Company currently maintains a full valuation allowance.

January

2016,

the FASB issued ASU

2016

01,

Financial Instruments Overall – Recognition and Measurement of Financial Assets and Liabilities (Topic

825

10)

(“ASU

2016

01”),

which provides several updates related to Topic

825

10.

This update applies to all entities that hold financial assets or owe financial liabilities. This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2017,

and interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

February

2016,

the FASB issued ASU

2016

02,

Leases (Topic

842)

(“ASU

2016

02”),

which requires lessees to recognize assets and liabilities for operating leases with lease terms greater than

twelve

months in the balance sheet. The update also requires improved disclosures to help users of financial statements better understand the amount, timing and uncertainty of cash flows arising from leases. ASU

2016

is effective for fiscal years beginning after

December

15,

2018,

including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

March

2016,

the FASB issued ASU

2016

06,

Derivatives and Hedging (Topic

815),

Contingent Put and Call Options in Debt Instruments

(“ASU

2016

06”),

which clarifies the requirements for assessing whether contingent call and put options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. ASU

2016

is effective for fiscal years beginning after

December

15,

2016,

including interim periods within those fiscal years, with early adoption permitted. The Company does not currently expect this standard to have a material effect on its financial statements and disclosures upon adoption.

In Ma

rch

2016,

the FASB issued ASU

2016

09,

Compensation–Stock Compensation (Topic

718),

Improvements to Employee Share-Based Payment Accounting

(“ASU

2016

09”),

which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU

2016

is effective for fiscal years beginning after

December

15,

2016,

August

2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows – Classification of Certain Cash Receipts and Cash Payments (Topic

230)

(“ASU

2016

15”),

which addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update applies to all entities that are required to present a statement of cash flows under Topic

230.

This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2017,

and interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

November

2016,

the FASB issued ASU

2016

18,

Statements of Cash Flows (Topic

320)

– Restricted Cash

(“ASU

2016

15”),

which addresses the treatment of restricted cash and restricted cash equivalents in the statement of cash flows. This update applies to all entities that have restricted cash or restricted cash equivalents and are required to present a statement of cash flows. This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2017,

and interim periods within those fiscal years.

The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

Note C - Prepaid Expenses and Other Current Assets

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Other Current Assets [Text Block]

C.	Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):

	December 31,
	2016		2015
Prepaid insurance	$	333	$	290
Other receivables		58		2,375
Other prepaid expenses and current assets		98		93
Total	$	489	$	2,758

Note D - Property and Equipment

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

D.	Property and Equipment

Property and equipment consists of the following (in thousands):

	December 31,
	2016			2015
Laboratory equipment	$	842		$	530
Furniture and office equipment		733			169
Computers and hardware		231			176
Leasehold improvements		769			6
Total property and equipment		2,575			881
Less: accumulated depreciation and amortization		(605	)		(478	)
Property and equipment, net	$	1,970		$	403

The Company leases various equipment and leasehold improvements under capital lease agreements. The assets under capital leases are included in property and equipment as follows (in thousands):

	December 31,
	2016			2015
Laboratory equipment	$	271		$	—
Furniture and office equipment		537			94
Leasehold improvements		59			—
Total property and equipment financed under a capital lease agreement		867			94
Less: accumulated depreciation and amortization		(31	)		(22	)
Property and equipment financed under a capital lease agreement, net	$	836		$	72

The estimated useful lives of property and equipment are as follows:

	Useful Life
Asset Category	(in years)
Laboratory equipment		10
Furniture and office equipment		5 - 10
Computers and hardware		3 - 7
Leasehold improvements		9

Depreciation and amortization expense, including amounts

pertaining to assets held under capital leases, was approximately

$175,000,

$84,000

and

$75,000

for the years ended

December

31,

2016,

2015

and

2014,

respectively.

Note E - Accounts Payable and Accrued Expenses

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]

E.	Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist

of the following (in thousands):

	December 31,		December 31,
	2016		2015
Accrued interest	$	2,222	$	698
Accrued banking fees		700		700
Accrued severance		646		—
Accrued payroll		1,024		947
Accounts payable		469		1,252
Other accrued expenses		1,383		1,309
Total	$	6,444	$	4,906

Note F - Debt Obligations

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Debt Disclosure [Text Block]

F.	Debt Obligations

Deerfield Facility Agreement

June

2014,

the Company entered into a

$60

million facility agreement (the “Deerfield Facility Agreement”) with Deerfield Private Design Fund III, LP (“Deerfield”). The

first

payment to the Company under the terms of the Deerfield Facility Agreement consisted of a term loan of

$15

million (the “Term Notes”) and a senior secured loan of

$10

million (the “Deerfield Convertible Notes”). Deerfield is no longer obligated to provide the Company any additional disbursements under the Deerfield Facility Agreement. All loans issued under the Deerfield Facility Agreement bear interest at

9.75%

per annum. Deerfield

may

convert any portion of the outstanding principal and any accrued but unpaid interest on the Deerfield Convertible Notes into shares of the Company’s common stock at an initial conversion price of

$5.85

per share.

The Company also issued to Deerfield a warrant to purchase

14,423,076

shares of Series D redeemable convertible preferred stock (“

Series D Preferred”) at an exercise price of

$0.78

per share, which is exercisable until

June

2024

(the “Deerfield Warrant”). Upon completion of the IPO, the Deerfield Warrant automatically converted into a warrant to purchase

1,923,077

shares of the Company’s common stock at an exercise price of

$5.85

per share. This warrant qualifies as a participating security under ASC Topic

260,

Earnings per Share,

and is treated as such in the earnings per share calculation (Note I). In the event that a Major Transaction occurs, as defined below, Deerfield

may

require the Company to redeem the Deerfield Warrant for a cash amount equal to the Black-Scholes value of the portion of the Deerfield Warrant to be redeemed (the “Put Option”). A Major Transaction is (i) a consolidation, merger, exchange of shares, recapitalization, reorganization, business combination or other similar event; (ii) the sale or transfer in

one

transaction or a series of related transactions of all or substantially all of the assets of the Company; (iii) a

third

-party purchase,

tender

or exchange offer made to the holders of outstanding shares, such that following such purchase,

tender

or exchange offer a change of control has occurred; (iv) the liquidation, bankruptcy, insolvency, dissolution or winding-up affecting the Company; (v) the shares of the Company’s common stock cease to be listed on any eligible market; and (vi) at any time, the shares of the Company’s common stock cease to be registered under Section

of the Securities Exchange Act of

1934,

as amended (the “Exchange Act”).

In addition, the Company issued to Deerfield

1,923,077

shares of Series D Preferred as consideration for the loans provided to the Company under the Deerfield Facility Agreement. Upon completion of the IPO, these shares automatically reclassified into

256,

410

shares of the Company’s common stock. The Company recorded the fair value of the shares of Series D Preferred of

$1.5

million, to debt issuance costs on the date of issuance. The Company recorded the fair value of the Deerfield Warrant and the embedded Put Option to debt discount on the date of issuance. The debt issuance costs and debt discount are amortized over the term of the related debt and the expense is recorded as interest expense in the statements of operations.

Pursuant to the Deerfield Fac

ility Agreement, the Company

may

not enter into specified transactions, including a debt financing in the aggregate value of

$750,000

or more, a merger, an asset sale or any other change of control transaction or any joint venture, partnership or other profit sharing arrangement, without the prior approval of Deerfield. Additionally, if the Company were to enter into a major transaction, including a merger, consolidation, sale of substantially all of its assets or other change of control transaction, Deerfield would have the ability to demand that prior to consummation of such transaction the Company repay all outstanding principal and accrued interest of any notes issued under the Deerfield Facility Agreement.

Under each warrant issued pursuant to the Deerfield facility, Deerfield has the right to demand that we redeem the warrant for a cash amount equal to the Black-Scholes value of a portion of the warrant upon the occurrence of specified events, including a merger, an asset sale or any other change of control transaction.

The Company

must repay

one

third

of the outstanding principal amount of all debt issued under the Deerfield Facility Agreement on the

fourth

and

fifth

anniversaries of the Deerfield Facility Agreement. The Company is then also obligated to repay the balance of the outstanding principal amount on

February

14,

2020.

The Company prepaid all outstanding interest and principal on the Term Notes in

February

2016.

Interest accrued on outstanding debt under the Deerfield Fa

cility Agreement is due quarterly in arrears. Upon notice to Deerfield, the Company

may

choose to have

one

or more of the

first

eight

of such scheduled interest payments added to the outstanding principal amount of the debt issued under the Deerfield Facility Agreement, provided that all such interest was due on

July

2016.

The Company elected this option on all

eight

of the scheduled interest payments through

June

30,

2016.

The accrued interest added to outstanding principal, was paid to Deerfield on

July

2016.

This accrued interest added to outstanding principal, is reflected as a cash outflow from financing activities in the statement of cash flows.

Second Amendment to Senior Secured Convertible Note and Warrant

January

2016,

the Company entered into a Second Amendment (the “Second Amendment”) to the Deerfield Convertible Notes and Deerfield Warrant, by and between the Company and Deerfield. The Second Amendment, among other things, clarified the calculation of an anti-dilution adjustment of the conversion price and exercise price of the Deerfield Convertible Notes and Deerfield Warrant, respectively, in the event that the Company effects a firm commitment underwritten public offering of its securities. Except as modified by the Second Amendment, the Third Amendment (as described below) and the Fourth Amendment (as described below), all terms and conditions of the Deerfield Convertible Notes and Deerfield Warrant remain in full force and effect

Issuance of

5.50%

Senior Convertible

Notes and Third Amendment to Senior Secured Convertible Note and Warrant

February

2016,

the Company issued

$86.25

million aggregate principal amount of its

5.50%

Senior Convertible Notes due

2021

(the “

2021

Notes”) to Cowen and Company, LLC and RBC Capital Markets, LLC., as representatives of the several initial purchasers (the “Initial Purchasers”), who subsequently resold the

2021

Notes to qualified institutional buyers (the “Note Offering”) in reliance on the exemption from registration provided by Rule

144A

under the Securities Act of

1933,

as amended (the “Securities Act”).

The net proceeds from the Note Offering were approximately

$82.8

million, after deducting the Initial Purchasers

’ discount and estimated offering expenses. Concurrent with the Note Offering, the Company used approximately

$18.6

million of the net proceeds from the Note Offering to repay in full the Term Notes, plus all accrued but unpaid interest, a make-whole interest payment and a prepayment premium on the Term Notes. This principal, accrued but unpaid interest, make-whole interest payment and prepayment premium on the Term Notes is reflected as a cash outflow from financing activities in the statement of cash flows.

The

2021

Notes were issued pursuant to an Indenture, dated as of

February

2016

(the “Indenture”), between the Company and U.S. Bank National Association, as trustee. Interest on the

2021

Notes is payable semi-annually in cash in arrears on

February

and

August

of each year, beginning on

August

2016,

at a rate of

5.50%

per year. The

2021

Notes mature on

February

2021

unless earlier converted or repurchased. The

2021

Notes are not redeemable prior to the maturity date, and no sinking fund is provided for the

2021

Notes.

The

2021

Notes are convertible at an initial conversion rate of

58.4454

shares of the Company

’s common stock per

$1,000

principal amount of the

2021

Notes, subject to adjustment under the Indenture, which is equal to an initial conversion price of approximately

$17.11

per share of common stock. Upon conversion, the

2021

Notes will be settled in shares of the Company’s common stock, together with a cash payment in lieu of delivering any fractional share. The conversion rate will be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date, the Company will increase the conversion rate for a holder who elects to convert its

2021

Notes in connection with such a corporate event in certain circumstances.

If the Company undergoes a “

fundamental change” (as defined in the Indenture), holders

may

require that the Company repurchase for cash all or any portion of their

2021

Notes at a fundamental change repurchase price equal to

100%

of the principal amount of the

2021

Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, holders who convert their

2021

Notes on or after the date that is

one

year after the last date of original issuance of the

2021

Notes

may

also be entitled to receive, under certain circumstances, an interest make-whole payment payable in shares of the Company’s common stock. The Company is bifurcating the fundamental change and make-whole interest payment provisions as embedded derivatives and marking them to fair value each reporting period (Note L).

The Indenture includes customary terms and covenants, including certain events of default after which the

2021

Notes

may

be due and payable immediately.

In connection with the Note Offering, on

February

2016,

the Company entered into a Third Amendment (the “Third Amendment”) to the Deerfield Facility Agreement, Deerfield Convertible Notes and Deerfield Warrant with Deerfield. The Third Amendment, among other things, eliminated the Company’s ability to require Deerfield to convert the Deerfield Convertible Notes into Company common stock. In addition, pursuant to the Third Amendment, Deerfield consented to the prepayment of the Term Notes and the issuance of the

2021

Notes. Except as modified by the Third Amendment and the Fourth Amendment (as described below), all terms and conditions of the Deerfield Facility Agreement remain in full force and effect.

Fourth Amendment to Deerfield Convertible Notes and Deerfield Warrant

In connection with entering into the

ATM Agreement, on

October

2016,

the Company entered into a Fourth Amendment (the “Fourth Amendment”) to the Deerfield Convertible Note and the Deerfield Warrant, by and between the Company and Deerfield. The Fourth Amendment, among other things, clarifies the calculation of an anti-dilution adjustment of the conversion price and exercise price of the Deerfield Convertible Note and Deerfield Warrant, respectively, in the event that the Company effects an “at the market offering” as defined in Rule

415

of the Securities Act of its common stock.

Line of Credit

During the

second

quarter of

2016,

the Company opened a

line of credit with a total borrowing capacity of

$1.1

million with City National Bank of Florida (the "Line of Credit Agreement") to support several irrevocable letters of credit issued by the bank on behalf of the Company. As of

December

31,

2016

the Company had unused letters of credit in the amount of

$0.4

million. The line of credit has a maturity date of

January

31,

2018.

As of

December

31,

2016,

the Company had no outstanding balance under the line of credit. The Line of Credit Agreement is collateralized by a restricted money market account, equal to the total amount of the borrowing capacity under the line of credit, held by the same bank institution. The money market account is reported as restricted cash on the balance sheet. The line of credit contains no financial covenants. Borrowings under the Line of Credit Agreement carry interest at a rate equal to the

-month London Interbank Offered Rate plus

2.00%

per annum. The interest rate under the Line of Credit Agreement was

2.77%,

as of

December

31,

2016.

Note G - Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

G.	Commitments and Contingencies

Legal Matters

From time to time, the Company is involved in various legal proceedings arising in the normal course of business. For some matters, a liability is not probable or the amount cannot be reasonably estimated and, therefore, an accrual has not been made. However, for such matters when it is probable that the Company has incurred a liability and can reasonably estimate the amount, the Company accrues and discloses such estimates. As of

December

31,

2016,

no accruals have been made related to commitments and contingencies

. As of

December

31,

2015,

the Company had accrued

$20,000

related to commitments and contingencies.

2014,

a former financial advisor of the Company filed a request with the Iowa District Court to declare valid a purported right of

first

refusal to serve as the Company

’s exclusive financial advisor for specified strategic transactions and to receive fees for the specified strategic transactions irrespective of whether any such specified transaction occurred during or after the term of the financial advisor’s service agreement. This filing by the former financial advisor was made in response to an action initiated by the Company in

2013

seeking a declaratory judgement finding that such purported right was invalid and unenforceable. Two former members of the Company’s board of directors (the “Board”) joined the lawsuit as intervenors based on the former financial advisor’s purported assignment of its rights, or a portion thereof, under the agreement to the intervenors. In

September

2015,

the court granted summary judgement in favor of the Company with respect to the Company’s declaratory judgement action and the former financial advisor’s counterclaims and the Company separately entered into settlement agreements with each of the intervenors. The settlements reached with the intervenors did not differ from the accrual previously recorded by the Company by a material amount. The former financial advisor subsequently filed a notice of appeal of the court’s ruling with the Supreme Court of Iowa. On

January

2016,

the Company entered into a Settlement Agreement and Mutual Release (the “Settlement Agreement”) with the former financial advisor and Donald DeWaay, Jr. pursuant to which, among other things, the former financial advisor agreed, in exchange for the consideration described therein, to dismiss with prejudice its pending appeal. DeWaay Financial Network’s appeal was subsequently dismissed by the Supreme Court of Iowa on

January

2016.

The settlement amount was commensurate with the contingency recorded in the books and records of the Company. The consideration in the settlement agreement did not differ from the accrual previously recorded by the Company by a material amount.

November

2016,

a stockholder filed a class action suit against the Company in the Iowa District Court in Johnson county alleging that the Company, certain of is senior executives and directors who signed the

registration statement in connection with its initial public offering, and each of the investment banks that acted as underwriters for the offering negligently issued untrue statements of material facts and omitted to state material facts required to be stated in the registration statement and incorporated offering materials that the Company filed with the U.S Securities and Exchange Commission in support of the offering. The plaintiff does not quantify any alleged damages in his complaint but, in addition to attorneys' fees and costs, the plaintiff seeks to recover damages and obtain other relief on behalf of himself and all other persons who purchased the Company's common stock pursuant or traceable to the offering and the registration statement and who were allegedly damaged thereby.

January

2017,

the suit was removed to the U.S. District Court for the Southern District of Iowa. The plaintiff has since filed a motion to remand the case to the Iowa District Court, and that motion is still pending. The suit is still in a preliminary stage and has not yet been set for trial. As such, the Company unable to predict the timing or outcome of this litigation as of the date of this report.

Lease Agreements

Iowa

The Company leases office and laboratory facilities in Iowa under a non-can

celable operating lease. The Company’s lease for its Iowa facilities expires in

September

2017

and includes a renewal option that could extend the lease for successive

one

year terms upon expiration.

Florida

The Company leases office space in Florida, comprised of

two

contiguous office suites, under a

non-cancelable operating lease, which

expires in

August

2025

and

February

2026,

respectively, and includes the right to extend the term of the lease for

two

successive

five

year terms upon expiration.

Virginia

The Company leases office and

laboratory facilities in Virginia under a non-cancelable operating lease.

February

2017,

the Company modified the lease to expand the amount of office space in the current facility.

The Company’s lease for its Virginia facilities expires in

August

2017.

North Carolina

The Company leases office space in North Carolina under a non-cancelable operating lease. The expiration date of the Company

’s lease is

May

2020,

and includes renewal options that could extend the lease for an additional

three

years.

Capital Lease

The Company leases various laboratory equipment, furniture and office equipment and leasehold improvements that are accounted for as capital leases and that require ongoing payments, including interest expense. The capital leases

are financed through various financial institutions and are collateralized by the underlying assets. As of

December

31,

2016,

the interest rates for assets under remaining capital leases were

7.19%

and

8.05%.

Rent expense for non-cancelable operating and capital leases was

$0.6

million,

$0.3

million and

$0.2

million for the years ended

December

31,

2016,

2015

and

2014,

respectively.

Future minimum lease payments under capital leases and non-cancelable operating leases as of

December

31,

2016,

were as follows (in thousands):

	Capital			Operating
Year Ending December 31,	Leases			Leases
2017	$	214		$	555
2018		208			585
2019		208			569
2020		208			499
2021		127			449
Thereafter		—			1,836
Total minimum lease payments		965		$	4,493
Less: amounts representing interest		(152	)
Total	$	813

Note H - Supply Arrangement

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Collaborative Arrangement Disclosure [Text Block]

H.	Supply Arrangement

As of

December

31,

2016,

the Company has

one

manufacturing arrangement that involves

potential future expenditures related to research and development.

November

2009,

the Company entered into a supply agreement (the “

Supply Agreement”) with Johnson Matthey Inc. (“JMI”) whereby JMI has agreed to supply the Company with all of the

KP201

necessary for clinical trials and commercial sale for a price equal to JMI’s manufacturing cost and to provide process optimization and development services for

KP201.

The Company’s product candidate,

KP201/IR,

contains

KP201

and is under development to treat acute pain.

expense was recorded under this agreement for the years ended

December

31,

2016,

2015

and

2014.

The Company must purchase all of its U.S.

KP201

needs from JMI and JMI cannot supply

KP201

to other companies. The term of the Supply Agreement extends as long as the Company holds a valid and enforceable patent for

KP201

or until the

tenth

anniversary of

KP201’s

commercial launch, whichever date is later. Upon the expiration of such term, the agreement will automatically renew for a period of

two

years unless either party provides

months prior notice of its intent not to renew. Under the agreement, JMI will receive a tiered-based royalty share on the net sales on the commercial sale of a FDA approved drug incorporating

KP201.

No reliable estimate of the future payments can be made at this time.

Note I - Preferred Stock and Warrants

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Preferred Stock [Text Block]

I.	Preferred Stock and Warrants

Authorized, Issued, and Outstanding Preferred Stock

April

2015,

the Company amended and restated its Certificate of Incorporation to decrease

the number of its authorized shares of preferred stock to

10,000,000

shares with a par value of

$0.0001

per share. As described in Note A, in

April

2015,

the Company completed an IPO of its common stock. Upon completion of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock were automatically converted or reclassified into an aggregate of

5,980,564

shares of the Company’s common stock. As of

December

31,

2016,

the Company had

10,000,000

shares of authorized and undesignated preferred stock, and did

not

have any preferred stock outstanding.

Preferred Stock Activity

The following table summarizes redeemable convertible preferred stock activity for the years ended

December

31,

2016,

2015

and

2014:

	Shares of
	Series A Preferred			Series B Preferred			Series C Preferred			Series D Preferred			Series D-1 Preferred			Total
Balance, January 1, 2014		9,704,215			6,220,000			18,557,408			—			—			34,481,623
Shares issued upon conversion of 2013 Convertible Notes		—			—			—			5,332,348			—			5,332,348
Shares issued for financing fee to Deerfield		—			—			—			1,923,077			—			1,923,077
Balance, December 31, 2014		9,704,215			6,220,000			18,557,408			7,255,425			—			41,737,048
Issuance of Series D-1 preferred stock		—			—			—			—			3,200,000			3,200,000
Exercise of Series D preferred warrants		—			—			—			3,205			—			3,205
Effect of reverse stock split		(8,410,377	)		(5,390,766	)		(16,083,286	)		(6,290,844	)		(2,784,416	)		(38,959,689	)
Less: Conversion of preferred stock into common stock upon IPO		(1,293,838	)		(829,234	)		(2,474,122	)		(967,786	)		(415,584	)		(5,980,564	)
Balance, December 31, 2015		—			—			—			—			—			—
Balance, December 31, 2016		—			—			—			—			—			—

Series D-

Redeemable Convertible Preferred Stock

February

2015,

the Company entered into a stock purchase

agreement with Cowen KP Investment LLC in which Cowen KP Investment LLC agreed to purchase and the Company agreed to sell

3,200,000

shares of the Company’s Series D-

redeemable convertible preferred stock for

$1.25

per share, or an aggregate of

$4.0

million. Upon completion of the IPO, these shares automatically converted into

415,584

shares of the Company’s common stock.

Warrants

As described in Note A, in

April

2015,

the Company completed an IPO of its common stock.

Upon completion of the IPO, warrants to purchase

15,499,324

shares of Series D preferred stock were reclassified into warrants to purchase

2,066,543

shares of the Company’s common stock.

During

2013,

the Company issued

$3.8

million of convertible notes and the warrants (the

“2013

Warrants”) to purchase

1,079,453

shares of equity securities in a future financing meeting specified criteria (a “Qualified Financing”). The

2013

Warrants allow the holders to purchase shares of the same class and series of equity securities issued in the Qualified Financing for an exercise price equal to the per share price paid by the purchasers of such equity securities in the Qualified Financing. When the Company entered into the Deerfield Facility Agreement, the

2013

Warrants became warrants to purchase

1,079,453

shares of Series D preferred stock. Upon completion of the IPO, the

2013

Warrants automatically converted into warrants to purchase

143,466

shares of the Company’s common stock at an exercise price of

$5.85

per share. The

2013

Warrants, if unexercised, expire on the earlier of

June

2019,

or upon a liquidation event.

June

2014,

pursuant to the terms of the Deerfiel

d Facility Agreement, the Company issued the Deerfield Warrant to purchase

14,423,076

shares of Series D preferred stock (Note F). The Company recorded the fair value of the Deerfield Warrant as a debt discount and a warrant liability. The Deerfield Warrant, if unexercised, expires on the earlier of

June

2024,

or upon a liquidation event. Upon completion of the IPO, the Deerfield Warrant automatically converted into a warrant to purchase

1,923,077

shares of the Company’s common stock at an exercise price of

$5.85

per share. The Company is amortizing the debt discount to interest expense over the term of the Deerfield Convertible Notes.

The Company determined that the

2013

Warrants and Deerfield Warrant should be recorded as a liabili

ty and stated at fair value at each reporting period upon inception. As stated above, upon completion of the IPO, the

2013

Warrants and the Deerfield Warrant automatically converted into warrants to purchase the Company’s common stock. The Company marked the

2013

Warrants to fair value and reclassified them to equity upon closing of the IPO. The Deerfield Warrant remains classified as a liability and is recorded at fair value at each reporting period since it can be settled in cash. Changes to the fair value of the warrant liability are recorded through the statements of operations as a fair value adjustment (Note L).

Note J - Common Stock and Warrants

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Stockholders' Equity Note Disclosure [Text Block]

J.	Common Stock and Warrants

Authorized, Issued, and Outstanding Common Shares

April

2015,

the Company amended its Certificate of

Incorporation to increase the number of its authorized shares of common stock to

250,000,000

shares. Of the authorized shares,

14,646,982

and

14,490,954

shares of common stock were issued and outstanding at

December

31,

2016

and

2015,

respectively.

Dec

ember

31,

2016

and

2015,

the Company had reserved authorized shares of common stock for future issuance as follows:

	December 31,
	2016		2015
Conversion of Deerfield Convertible Notes		1,751,296		1,991,219
Conversion of 2021 Notes		5,040,914		—
Outstanding awards under equity incentive plans		1,990,260		1,397,511
Outstanding common stock warrants		2,087,477		2,325,383
Possible future issuances under equity incentive plans		1,244,671		1,410,848
Total common shares reserved for future issuance		12,114,618		7,124,961

Common Stock Activity

The following table summarizes common stock activity for the year ended

December

31,

2016,

2015

and

2014:

	Shares of
	Common Stock
Balance at January 1, 2014		2,381,041
Balance at December 31, 2014		2,381,041
Issuance of common stock in connection with the IPO		5,854,545
Conversion of preferred stock to common stock in connection with the IPO		5,980,564
Common stock warrants exercised		270,038
Common stock options exercised		4,766
Balance at December 31, 2015		14,490,954
Common stock warrants exercised		141,095
Common stock options exercised		14,933
Balance at December 31, 2016		14,646,982

The Company calculates the fair value of

common stock warrants using a Monte Carlo simulation. There were warrants exercised for an aggregate of

141,095

and

270,038

shares of common stock during the years ended

December

31,

2016

and

2015,

respectively.

warrants were exercised during the year ended

December

31,

2014.

From

2008

through

2012,

the Company issued warrants to purchase

595,920

shares of common stock in its private placement offerings of Series A redeemable convertible preferred stock, Series B redeemable convertible preferred stock and Series C redeemable convertible preferred stock (the “Underwriter Warrants”) and for leasing laboratory space. The Company accounted for the Underwriter Warrants as a derivative liability, which is adjusted to fair value at each reporting period, with the change in fair value recorded within other expenses in the statements of operations.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e))
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Topic 210
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

+ Details

Note K - Stock-based Compensation

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Disclosure of Compensation Related Costs, Share-based Payments [Text Block]

K.	Stock-Based Compensation

The Company maintains a stock-based compensation plan (the “

Incentive Stock Plan”) that governs stock awards made to employees and directors prior to completion of the IPO.

November

2014,

the Board, and in

April

2015,

the Company

’s stockholders, approved the Company’s

2014

Equity Incentive Plan (the

“2014

Plan”) which became effective in

April

2015.

The

2014

Plan provides for the grant of stock options, other forms of equity compensation, and performance cash awards. The maximum number of shares of common stock that

may

be issued under the

2014

Plan is

2,846,304,

as of

December

31,

2016.

In addition, the number of shares of common stock reserved for issuance under the

2014

Plan will automatically increase on

January

of each year, beginning on

January

2016,

and ending on and including

January

2024,

of the total number of shares of the Company’s capital stock outstanding on

December

of the preceding calendar year, or a lesser number of shares determined by the Board. Pursuant to the terms of the

2014

Plan, on

January

2017,

the common stock reserved for issuance under the

2014

Plan automatically increased by

585,879

shares.

During the year ended

December

31,

2016,

stock options to acquire

14,933

shares of common stock were exercised for approximately

$71,000

with an intrinsic value of

$169,000.

During the year ended

December

31,

2015,

stock options to acquire

4,766

shares of common stock were exercised for approximately

$28,000

with an intrinsic value of

$54,000.

No stock options were exercised during the year ended

December

31,

2014.

Stock-based compensation expense recorded unde

r the Incentive Stock Plan and the

2014

Plan is included in the following line items in the accompanying statements of operations (in thousands):

	Year ended December 31,
	2016		2015		2014
Research and development	$	1,051	$	610	$	62
General and administrative		3,639		1,759		152
Severance expense		1,910		—		—
	$	6,600	$	2,369	$	214

Stock Option Awards

The Company estimates the fair value of stock options using the Black-Scholes option-pricing model, which requires the use of subjective assumptions, including the expected term of the option, the expected stock price volatility, expe

cted dividend yield and the risk-free interest rate for the expected term of the option. The expected term represents the period of time the stock options are expected to be outstanding. Due to the lack of sufficient historical exercise data to provide a reasonable basis upon which to otherwise estimate the expected term of the stock options, the Company uses the simplified method to estimate the expected term for its “plain vanilla” stock options. Under the simplified method, the expected term of an option is presumed to be the mid-point between the vesting date and the end of the contractual term. Some options, for example those that have exercise prices in excess of the fair value of the underlying stock, are not considered “plain vanilla” stock options. For these options, the Company uses an expected term equal to the contractual term of the option. Expected volatility is based on historical volatilities for publicly traded stock of comparable

compan

ies over the estimated expected term of the stock options. The Company assumes no dividend yield because dividends are not expected to be paid in the near future, which is consistent with the Company’s history of not paying dividends.

The Company recogni

zes compensation expense related to stock-based payment transactions upon satisfaction of the requisite service or vesting requirements. Forfeitures are estimated at the time of grant and revised based on actual forfeitures, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

Using the Black-Scholes option-pricing model, the weighted-average fair value of awards granted during the years ended

December

31,

2016,

2015

and

2014,

fair value was

$9.25,

$10.63

and

$4.50

per sha

re, respectively. The assumptions used to estimate fair value are as follows:

	December 31,		December 31,		December 31,
	2016		2015		2014
Risk-free interest rate		1.29% - 1.50%		1.40% - 1.99%		0.91% - 2.70%
Expected term (in years)		5.50 - 6.26		4.33 - 6.25		7.00 - 10.00
Expected volatility		77.38% - 94.78%		68.79% - 86.84%		86.00% - 95.00%
Expected dividend yield		0%		0%		0%

The activity under the Incentive Stock Plan and the

2014

Plan

for the year ended

December

31,

2016,

is summarized as follows:

						Weighted Average
	Number of			Weighted Average		Remaining Contractual		Aggregate Intrinsic
	Options			Exercise Price		Term (in years)		Value
Outstanding balance at January 1, 2016		1,397,511		$	13.28		8.58	$	9,204,403
Granted		959,375		$	13.31
Exercised		(14,933	)	$	4.78
Canceled, forfeited or expired		(351,693	)	$	11.65
Outsta nding balance at December 31, 2016		1,990,260		$	13.64		8.27	$	26,400
Exercisable at December 31, 2016		637,492		$	10.77		6.78	$	26,400
Vested and expected to vest at December 31, 2016		1,978,260		$	13.62		8.27	$	26,400

Information regarding currently outstanding and exercisable options as of

December

31,

2016,

is as follows:

		Options Outstanding				Options Exercisable
				Weighted Average				Weighted Average
		Number of		Remaining Contractual		Number of		Remaining Contractual
Exercise Price		Shares		Term (in years)		Shares		Term (in years)
$	0.75		12,000		0.50		12,000		0.50
$	3.00		20,666		1.54		20,666		1.54
$	3.80		99,000		9.81		—		—
$	4.65		35,994		2.06		35,994		2.06
$	5.85		298,661		6.26		261,661		6.07
$	6.05		50,000		9.40		—		—
$	8.63		21,306		8.12		10,826		8.15
$	11.00		21,333		8.25		5,333		8.25
$	11.41		88,000		8.41		88,000		8.41
$	12.62		340,000		9.11		—		—
$	13.96		22,500		9.13		—		—
$	16.06		12,000		9.26		—		—
$	16.25		98,750		9.17		—		—
$	16.31		13,500		9.17		—		—
$	16.61		11,250		8.93		2,812		8.93
$	17.93		4,500		9.27		—		—
$	18.10		140,000		9.29		—		—
$	18.29		205,000		8.48		51,250		8.48
$	18.38		54,000		9.28		—		—
$	18.61		32,000		8.65		8,000		8.65
$	19.02		62,000		8.65		54,000		8.65
$	20.45		335,000		8.68		83,750		8.68
$	21.37		6,400		8.69		1,600		8.69
$	22.12		6,400		8.70		1,600		8.70
			1,990,260		8.27		637,492		6.78

The total fair value of stock options vested during the years ended

December

31,

2016,

2015

and

2014,

was

$5.4

million,

$1.1

million and

$0.2

million, respectively.

Unvested stock options as of

December

31,

2016

and

2015,

were as follows:

		Number of Unvested Shares
		December 31,		December 31,
Exercise Price		2016		2015
$	3.80		99,000		—
$	5.85		37,000		97,633
$	6.05		50,000		—
$	8.63		10,480		147,973
$	11.00		16,000		21,333
$	11.41		—		82,035
$	12.62		340,000		—
$	13.96		22,500		—
$	16.06		12,000		—
$	16.25		98,750		—
$	16.31		13,500		—
$	16.61		8,438		11,250
$	17.93		4,500		—
$	18.10		140,000		—
$	18.29		153,750		205,000
$	18.38		54,000		—
$	18.61		24,000		38,400
$	19.02		8,000		62,000
$	20.45		251,250		335,000
$	21.37		4,800		6,400
$	22.12		4,800		6,400
			1,352,768		1,013,424

As of

December

31,

2016,

there was

$10.6

million of total unrecognized compensation cost related to unvested share-based compensation arrangements granted under the I

ncentive Stock Plan and

2014

Plan. That compensation cost is expected to be recognized over a weighted-average period of

2.86

years.

During the year ended

December

31,

2016,

the Company recognized

$44,000

of stock-based compensation expense r

elated to performance-based awards included in research and development expenses. These awards were in connection with the strategic initiatives set for the award that were achieved in

2016

exercisable for an aggregate of

13,333

shares of common stock during the year ended

December

31,

2016.

During the year ended

December

31,

2015,

the Company recognized

$0.7

million of stock-based compensation expense r

elated to performance-based awards included in general and administrative expenses and

$0.2

million of stock-based compensation expense related to performance-based awards included in research and development expenses. These awards were in connection with the grant of fully vested stock options exercisable for an aggregate of

163,998

shares of common stock during the year ended

December

31,

2015.

The Company did not recognize any stock-based compensation expense related to performance-based incentive awards during

the year ended

December

31,

2014,

since the strategic initiatives set for the awards were not achieved or probable of achievement.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Note L - Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Fair Value Disclosures [Text Block]

L.	Fair Value of Financial Instruments

The

carrying amounts of certain financial instruments, including cash and cash equivalents, restricted cash and accounts payable, approximate their respective fair values due to the short-term nature of such instruments.

The fair value of the Deerfield Convertible Notes

was

$10.2

million and

$42.0

million, respectively, at

December

31,

2016

and

2015.

The fair value of the

2021

Notes, which were issued during the

first

quarter of

2016,

was

$46.3

million at

December

31,

2016.

Both the Deerfield Convertible Notes and

2021

Notes fall within Level

of the fair value hierarchy as their value is based on the credit worthiness of the Company, which is an unobservable input.

The Company used a Tsiveriotis-Fernandes model to value the Deerfield Convertible Notes

December

31,

2016

and

2015

and the

2021

Notes at

December

31,

2016.

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level in whi

ch to classify them for each reporting period. This determination requires significant judgments to be made. The following table summarizes the conclusions reached regarding fair value measurements as of

December

31,

2016

and

2015

(in thousands):

			Quoted Prices in
	Balance at		Active Markets for		Significant Other		Significant
	December 31,		Identical Assets		Observable Inputs		Unobservable Inputs
	2016		(Level 1)		(Level 2)		(Level 3)
Underwriter Warrant liability	$	16	$	—	$	—	$	16
Deerfield Warrant liability		4,231		—		—		4,231
Embedded Put Option		365		—		—		365
Fundamental change and make-whole interest provisions embedded in 2021 Notes		6		—		—		6
Total liabilities	$	4,618	$	—	$	—	$	4,618
Trading securities:
Certificates of deposit		7,788		7,788		—		—
U.S. Treasury securities		37,066		37,066		—		—
U.S. government-sponsored agency securities		14,349		—		14,349		—
Total assets	$	59,203	$	44,854	$	14,349	$	—

			Quoted Prices in
	Balance at		Active Markets for		Significant Other		Significant
	December 31,		Identical Assets		Observable Inputs		Unobservable Inputs
	2015		(Level 1)		(Level 2)		(Level 3)
Underwriter Warrant liability	$	3,877	$	—	$	—	$	3,877
Deerfield Warrant liability		33,750		—		—		33,750
Embedded Put Option		212		—		—		212
Total liabilities	$	37,839	$	—	$	—	$	37,839
Trading securities:
Certificates of deposit		8,951		8,951		—		—
U.S. Treasury securities		4,996		4,996		—		—
U.S. government-sponsored agency securities		5,055		5,055		—		—
Total assets	$	19,002	$	19,002	$	—	$	—

The Company

’s Underwriter Warrant liability, Deerfield Warrant liability, embedded Put Option and the fundamental change and the make-whole interest provisions embedded in the

2021

Notes, as well as the trading securities are measured at fair value on a recurring basis. As of

December

31,

2016

and

2015,

the Underwriter Warrant liability, Deerfield Warrant liability and embedded Put Option are reported on the balance sheet in derivative and warrant liability, while the trading securities are reported on the balance sheet in marketable securities and long-term investments. The

2021

Notes were issued during the

first

quarter of

2016

and the fundamental change and make-whole interest provisions embedded in the

2021

Notes are reported on the balance sheet in derivative and warrant liability. The Company used a Monte Carlo simulation to value the Underwriter Warrant liability, Deerfield Warrant liability and the embedded Put Option at

December

31,

2016

and

2015.

A Monte Carlo simulation was also used to value the fundamental change and make-whole interest provisions embedded in the

2021

Notes as of the issuance date and

December

31,

2016.

Significant unobservable inputs used in measuring the fair value of these financial instruments included the Company’s estimated enterprise value, an estimate of the timing of a liquidity or fundamental change event, a present value discount rate and an estimate of the Company’s stock volatility using the volatilities of guideline peer companies. Changes in the fair value of the Underwriter Warrant liability, the Deerfield

Warrant liability, the embedded Put Option and the fundamental change and make-whole interest provisions embedded in the

2021

Notes are reflected in the statements of operations as a

fair value adjustment.

A reconciliation of the beginning and ending balances for the derivative and warrant liability measured at fair value on a recurring basis using signific

ant unobservable inputs (Level

is as follows (in thousands):

	2016			2015
Balance at beginning of period	$	37,839		$	15,966
Reclassification of 2013 warrants to equity		—			(1,110	)
Exercise of warrants		(756	)		(4,293	)
Adjustment to fair value		(32,465	)		27,276
Balance at end of period	$	4,618		$	37,839

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Note M - Income Taxes

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Income Tax Disclosure [Text Block]

M.	Income Taxes

The Company

’s financial statements include a total state tax benefit of

$15,000,

$15,000

and

$22,000

on a loss before income taxes of

$16.5

million,

$54.6

million and

$24.5

million for the years ended

December

31,

2016,

2015

and

2014,

respectively. A reconciliation of the difference between the benefit for income taxes and income taxes at the statutory U.S. federal income tax rate is as follows (in thousands):

	Year ended December 31,
	2016			2015			2014
Federal statutory rate		34.00	%		34.00	%		34.00	%
Effect of:
Change in valuation allowance		(69.31	)		(19.25	)		(32.88	)
Return to provision and deferred true-up		(23.83	)		—			0.36
Change in rate		(14.63	)		—			—
State tax benefit (net of federal)		15.64			4.06			5.96
Warrant liability		68.44			(15.28	)		(9.39	)
State research and development credit		0.09			0.03			0.09
Federal research and development credit		5.65			0.84			3.29
Amortization		(3.15	)		—			—
Conversion feature and put option on 2013 convertible notes		—			(1.68	)		(1.26	)
Interest expense		—			—			0.21
Stock-based compensation		(12.71	)		(1.28	)		—
Other		(0.10	)		(1.42	)		(0.29	)
Federal income tax provision effective rate		0.09	%		0.02	%		0.09	%

The components of deferred tax assets and liabilities are as follows (in thousands):

	December 31,			December 31,			December 31,
	2016			2015			2014
Deferred tax assets relating to:
Net operating loss carryforwards	$	44,984		$	26,617		$	16,390
Research and development tax carryforward		3,166			2,254			1,793
Compensation		715			232			83
Total gross deferred tax assets		48,865			29,103			18,266
Deferred tax liabilities relating to:
Property and equipment		89			80			170
Total gross deferred tax liabilities		89			80			170
Deferred tax assets less liabilities		48,776			29,023			18,096
Valuation allowance		(48,776	)		(29,023	)		(18,096	)
Net deferred tax asset (liability)	$	—		$	—		$	—

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax

assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Based upon the level of historical taxable income and projections for future taxable income over the periods in which the deferred tax assets are deductible, management believes it is more likely than not that the Company will not realize the benefits of these deductible differences in the future.

The Company had the following federal net operating loss carryforward and research activities credits as of

December

31,

2016

(in thousands):

	Net Operating		Research
Year Incurred	Loss Carryforwards		Activities Credit		Expiration
2007	$	454	$	30		2027
2008		1,178		65		2028
2009		3,060		176		2029
2010		3,423		149		2030
2011		9,929		176		2031
2012		—		170		2032
2013		4,353		133		2033
2014		15,819		894		2034
2015		24,189		461		2035
2016		40,959		912		2036
	$	103,364	$	3,166

The Company also has certain state net operating loss carryforwards totaling

$108.6

million that expire between

2027

and

2036.

Due to potential ownership changes that

may

have occurred or would occur in the future, IRC Section

382

may

place additional l

imitations on the Company’s ability to utilize the net operating loss carryforward.

Financial Interpretation No.

(“

FIN

48”),

Accounting for Uncertainty in Income Taxes

, uses the term “more likely than not” to evaluate whether or not a tax position will be sustained upon examination. The Company has not identified any tax positions that do not meet the more likely than not threshold.

Note N - Net Loss Per Share

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Earnings Per Share [Text Block]

N.	Net Loss Per Share

Under the

two

-class method, for periods with net income, basic net income per common share

is computed by dividing the net income attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. Net income attributable to common stockholders is computed by subtracting from net income the portion of current year earnings that participating securities would have been entitled to receive pursuant to their dividend rights had all of the year’s earnings been distributed. No such adjustment to earnings is made during periods with a net loss as the holders of the participating securities have no obligation to fund losses. Diluted net loss per common share is computed under the

two

-class method by using the weighted average number of shares of common stock outstanding plus, for periods with net income attributable to common stockholders, the potential dilutive effects of stock options and warrants. In addition, the Company analyzes the potential dilutive effect of the outstanding participating securities under the if-converted method when calculating diluted earnings per share in which it is assumed that the outstanding participating securities convert into common stock at the beginning of the period. The Company reports the more dilutive of the approaches

(two

-class or if-converted) as its diluted net income per share during the period.

The following table summarizes the computation of basic and diluted net loss and net loss per share of the Company (in thousands, except share and pe

r share amounts):

	Year ended December 31,
	2016			2015			2014
Net loss - basic and diluted	$	(16,516	)	$	(54,664	)	$	(24,455	)
Weighted-average number of common shares - basic and diluted		14,597,053			7,368,681			2,381,041
Net loss per share - basic and diluted	$	(1.13	)	$	(7.42	)	$	(10.27	)

Diluted net loss per share is the same as basic net loss per share for all periods presented because the effects of potentially dilutive items were anti-dilutive given the Company

’s net loss. The following securities, presented on a common stock equivalent basis, have been excluded from the calculation of weighted average common shares outstanding because their effect is anti-dilutive:

	December 31,		December 31,		December 31,
	2016		2015		2014
Redeemable convertible preferred stock:
Series A		—		—		1,293,838
Series B		—		—		829,234
Series C		—		—		2,474,122
Series D		—		—		967,359
Total redeemable convertible preferred stock		—		—		5,564,553
Warrants to purchase common stock		2,087,477		2,325,383		595,920
Warrants to purchase Series D preferred stock		—		—		2,066,970
Awards under equity incentive plans		1,990,260		1,397,511		395,185
Deerfield Convertible Notes		1,751,296		1,991,219		1,808,353
2021 Notes		5,040,914		—		—
Total		10,869,947		5,714,113		10,430,981

Note O - Severance Expense

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Restructuring and Related Activities Disclosure [Text Block]

O.	Severance Expense

September

15,

2016,

the Company announced its intention to defer its commercial operations and realign its financial resources and operational priorities towards its product development pipeline. The activities related to the deferral and realignment were completed during the year ended

December

31,

2016.

As part of these activities, the Company reduced its workforce by

three

employees. Personnel and other related charges of approximately

$1.1

million and stock compensation expense of approximately

$1.9

million related to the acceleration of vesting on certain stock options, related to the workforce reduction, are presented as severance expense in the statements of operations. As of

December

31,

2016,

the Company had accrued severance expense recorded within accounts payable and accrued expenses in the amount of

$0.6

million.

Note P - Employee Benefit Plan

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Compensation and Employee Benefit Plans [Text Block]

P.	Employee Benefit Plan

The Company has a

401(k)

retirement plan (the “

401(k)

Plan”) that covers substantially all employees. The Company

may

provide a discretionary match with a maximum amount of

of the participant’s compensation, which vests immediately. The Company made matching contributions under the

401(k)

Plan of

$213,000,

$113,000

and

$69,000

for the years ended

December

31,

2016,

2015

and

2014,

respectively.

The Company has a discretionary profit sharing plan (the “

Profit Sharing Plan”) that covers all employees. Employees become eligible participants in the Profit Sharing Plan once they have provided

three

years of service to the Company. The Company made

contributions to the Profit Sharing Plan in

2016,

2015

2014.

Note Q - Quarterly Results of Operations (unaudited)

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Quarterly Financial Information [Text Block]

Q.	Quarterly Results of Operations (unaudited)

The following tables set forth unaudited quarterly statements of operations data for each of the quarters indicated. The financial statements for each of these quarters have been prepared on the same basis as the audited financial statements included herein and, in the opinion of management, include all adjustments, consisting only of normal recurring adjustments, necessary for the fair statement of the results of operations for these perio

ds. You should read this information together with our financial statements and related notes included herein. These quarterly

operating results are not necessarily indicative of the results for any future period.

	Three-Months Ended
	Dec 31,			Sep 30,			Jun 30,			Mar 31,			Dec 31,			Sep 30,			Jun 30,			Mar 31,
	2016			2016			2016			2016			2015			2015			2015			2015
Revenue	$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—
Operating expenses:
Research and development		7,963			4,287			4,988			3,234			4,716			4,328			2,768			2,119
General and administrative		2,873			3,104			4,287			3,736			2,566			2,152			3,188			977
Restructuring charges		—			3,010			—			—			—			—			—			—
Total operating expenses		10,836			10,401			9,275			6,970			7,282			6,480			5,956			3,096
Loss from operations		(10,836	)		(10,401	)		(9,275	)		(6,970	)		(7,282	)		(6,480	)		(5,956	)		(3,096	)
Other (expense) income:
Loss on extinguishment of debt		—			—			—			(4,740	)		—			—			—			—
Interest expense related to amortization of debt issuance costs and discount		(391	)		(390	)		(393	)		(442	)		(475	)		(479	)		(477	)		(477	)
Interest expense on principal		(1,445	)		(1,441	)		(1,475	)		(1,150	)		(698	)		(687	)		(654	)		(632	)
Fair value adjustment		2,723			(1,299	)		20,763			10,278			(764	)		(2,089	)		(22,661	)		(1,762	)
Interest and other income		9			98			144			102			15			11			5			—
Total other income (expense)		896			(3,032	)		19,039			4,048			(1,922	)		(3,244	)		(23,787	)		(2,871	)
(Loss) income before income taxes		(9,940	)		(13,433	)		9,764			(2,922	)		(9,204	)		(9,724	)		(29,743	)		(5,967	)
Income tax benefit (expense)		4			19			4			(12	)		1			(20	)		—			(7	)
Net (loss) income	$	(9,936	)	$	(13,414	)	$	9,768		$	(2,934	)	$	(9,203	)	$	(9,744	)	$	(29,743	)	$	(5,974	)

Net (loss) income per share:
Basic	$	(0.68	)	$	(0.92	)	$	0.59		$	(0.20	)	$	(0.64	)	$	(0.68	)	$	(2.45	)	$	(2.50	)
Diluted	$	(0.68	)	$	(0.92	)	$	(0.58	)	$	(0.20	)	$	(0.64	)	$	(0.68	)	$	(2.45	)	$	(2.50	)

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Stockholders' Equity, Policy [Policy Text Block]

Reverse Stock Split

April

2015,

the Company effected a

-for-

7.5

reverse stock split of its issued common stock. All applicable share data, per share amounts and related information in the financial statements and notes thereto have been adjusted re

troactively to give effect to the

-for-

7.5

reverse stock split.

Initial Public Offering

April

2015,

the Company completed an initial public offering (“IPO”) of its common stock. In connection with the initial closing of the IPO, the Company sold an aggregate of

5,090,909

shares of common stock at a price to the public of

$11.00

per share. In

May

2015,

the underwriters in the IPO exercised their option to purchase additional shares pursuant to which the Company sold an additional

763,636

shares of common stock at a price equal to the public price of

$11.00

per share. In the aggregate, net proceeds from the IPO, including net proceeds from the underwriter

s’ exercise of their option to purchase additional shares, were

$59.9

million, after deducting underwriting discounts and commissions of

$4.5

million. In addition, offering expenses totaled

$2.8

million. Upon completion of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock were converted or reclassified into

5,980,564

250,000,000

shares, designated as common stock, and

10,000,000

shares, designated as preferred stock, each with a par value of

$0.0001

per share.

Entry into

ATM Agreement

October

2016,

the Company entered into a Common Stock Sales Agreement (the “

ATM Agreement”) with Cowen and Company (“Cowen”) under which the Company

may

offer and sell, from time to time, in its sole discretion, shares of common stock having an aggregate offering price of up to

$50,000,000

through Cowen as the Company's sales agent. The registration statement on Form S-

included a prospectus covering the offering up to

$20,000,000

of shares of common stock in accordance with the ATM Agreement.

The Company

’s registration statement on Form S-

contemplated under the ATM Agreement was declared effective by the SEC on

October

17,

2016.

Cowen

may

sell common stock under the

ATM Agreement by any method permitted by law deemed to be an “at the market offering” as defined in Rule

415

may

impose). The Company will pay Cowen a commission of up to

three

percent

(3.0%)

of the gross sales proceeds of any common stock sold through Cowen under the ATM Agreement, and also has provided Cowen with customary indemnification rights.

The Company is not obligated to make any sales of common stock under the

As of

December

31,

2016,

the Company had deferred offering costs recorded within other long-term assets in the amount of

$0.2

million.

Basis of Accounting, Policy [Policy Text Block]

KemPharm, Inc. (the “

October

30,

2006,

and incorporated in Iowa, and reorganized in Delaware on

May

30,

2014.

The Company has experienced recurring losses from

operations and negative operating cash flows due to its ongoing research and development of its potential product candidates. The Company also has an accumulated deficit at

December

31,

2016.

Reclassification, Policy [Policy Text Block]

Reclas

sifications

During the

first

quarter of

2016

, the Company adopted Accounting Standards Update (“ASU”)

2015

03,

Interest – Imputation of Interest (Subtopic

835

30)

(“ASU

2015

03”),

2015

reduced the Company’s assets and liabilities by the amount of the debt issuance costs, which was

$1.1

million at

December

31,

2015.

This reclassification had no effect on reported net loss or cash flows.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP")

requires the Company to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

On an ongoing basis, the Company evaluates its estimates, includ

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of Credit Risk

Financial instruments that potentially expose

the Company to concentrations of credit risk consist principally of cash on deposit with multiple financial institutions, the balances of which frequently exceed insured limits.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

The Company considers any highly liquid investm

ents with an original maturity of

three

months or less to be cash equivalents.

Marketable Securities, Policy [Policy Text Block]

Marketable Securities and Long-term Investments

The Company maintains investment securities that are classified as trading securities. These securities are carried at fair value with unreali

December

31,

2016

and

2015,

respectively, the Company held marketable securities and long-term investments with an aggregate fair value of

$50.4

million and

$10.1

million that contained aggregate unrealized losses of

$50,000

and

$6,000,

respectively. These marketable securities and long-term investments have been in a continuous unrealized loss position for less than

months and the Company expects these investments to fully recovery prior to their maturity.

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment

The Company records property and equipment at cost less accumulated

three

fifteen

Debt, Policy [Policy Text Block]

Debt Issuance Costs

Debt issuance costs incurred in connection with financing arrangements are amortiz

ed over the life of the respective financing arrangement using the effective interest method.

Collaborative Arrangement, Accounting Policy [Policy Text Block]

Supply Arrangements

The Company enters into supply arrangements for the supply of components of its product candidates. These arrangements also

may

include a

share of future revenue if related product candidates reach commercialization. Costs under these supply arrangements, if any, are expensed as incurred (Note H).

Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]

Impairment of Long-Lived Assets

Long-lived assets to be held and used are reviewed for

impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets

may

such impairment occurred for the years ended

December

31,

2016,

2015

and

2014.

Fair Value of Financial Instruments, Policy [Policy Text Block]

Fair Value of Financial Instruments

The Company uses a

three

equent to their initial measurement. The hierarchy requires the Company to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value. The

three

tiers are defined as follows:

●

Level

—Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets;

●

Level

—Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities; and

●

Level

—Unobservable inputs that are supported by little or no market data, which require the Company to develop its own assumptions.

Research and Development Expense, Policy [Policy Text Block]

Research and Development

The Company records nonrefundable advance payments it makes for future research and development activities as prepaid expenses. Prepaid

expenses are recognized as expense in the statements of operations as the Company receives the related goods or services.

Intangible Assets, Finite-Lived, Policy [Policy Text Block]

Patent Costs

Patent costs, including related legal costs, are expensed as incurred and recorded within general and administrative

expenses on the statements of operations.

Income Tax, Policy [Policy Text Block]

Income Taxes

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax basis of assets and liabilities,

Uncertain tax positions are recognized only when the Company believes it is more likely than not tha

December

31,

2016

and

2015.

The Company files income tax returns in the United States for federal and various state jurisdictions. With few exceptions,

the Company is no longer subject to U.S. federal and state and local income tax examinations for years prior to

2012,

although carryforward attributes that were generated prior to

2012

may

still be adjusted upon examination by the Internal Revenue Service if used in a future period. No income tax returns are currently under examination by taxing authorities.

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Stock-Based Compensation

The Company measures and recognizes compensation expense for all stock-based payment awards made to employees, officers an

505

50.

Earnings Per Share, Policy [Policy Text Block]

Basic and Diluted Net

Loss per Share of Common Stock

The Company uses the

two

-class method to compute net loss per common share because the Company has issued securities, other than common stock, that contractually

entitle the holders to participate in dividends and earnings of the Company. The

two

Segment Reporting, Policy [Policy Text Block]

Segment and Geographic Information

Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is ava

December

31,

2016

and

2015.

New Accounting Pronouncements, Policy [Policy Text Block]

Application of New or Revised Accounting Standards

—Adopted

April

2012,

President Obama signed the Jump-Start Our Business Startups Act (the “

JOBS Act”) into law. The JOBS Act contains provisions that, among other things, reduce certain reporting requirements for an emerging growth company. As an emerging growth company, the Company

may

June

2014,

the FASB

issued ASU

2014

12,

Compensation–Stock Compensation

(Topic

718):

Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period

(“ASU

2014

12”).

The amendments require that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. ASU

2014

is effective for annual periods and interim periods within those annual periods beginning after

December

15,

2015.

Entities

may

apply ASU

2014

effective

January

2016.

The adoption of ASU

2014

did not have a material impact on the financial statements as the Company does not have any performance-based awards whereby performance could be achieved after the requisite service period.

August

2014,

the FASB issued ASU No.

2014

15,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

(“ASU

2014

15”),

which amends ASC Subtopic

205

(1)

provide a definition of the term “substantial doubt,”

(2)

require an evaluation every reporting period,

(3)

provide principles for considering the mitigating effect of management’s plans,

(4)

require certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans,

(5)

require an express statement and other disclosures when substantial doubt is not alleviated and

(6)

require an assessment for a period of

one

year after the date that financial statements are issued. ASU

2014

is effective for fiscal years ending after

December

15,

2016,

and for annual periods and interim periods thereafter.

The adoption of ASU

2014

did not have a material impact on the Company

’s financial statements as the Company determined there was no substantial doubt about its ability to continue as a going concern as of

December

31,

2016.

January

2015,

the FASB issued ASU No.

2015

01,

Income Statement - Extraordinary and Unusual Items (Subtopic

225

20);

Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU

2015

01”)

, which eliminates from GAAP the concept of extraordinary items, stating that the concept causes uncertainty because

(1)

it is unclear when an item should be considered both unusual and infrequent and

(2)

users do not find the classification and presentation necessary to identify those events and transactions. ASU

2015

is effective for fiscal years, and interim periods within those fiscal years, beginning after

December

15,

2015.

The Company adopted ASU

2015

effective

January

2016.

The adoption of ASU

2015

did not have a material impact on the Company’s financial statements as the Company had no extraordinary and/or unusual items recorded in prior periods.

April

2015,

the FASB issued ASU

2015

03,

which requires the debt issuance costs relate

December

15,

2015,

and interim periods within those fiscal years. The adoption of ASU

2015

reduced the Company’s assets and liabilities by the amount of the debt issuance costs, which was

$1.1

million at

December

31,

2015.

This reclassification had no effect on reported net loss or cash flows.

New Accounting Pronouncements, Not Yet Adopted, Policy [Policy Text Block]

Application of New or Revised Accounting Standards

—Not Yet Adopted

May

2014,

the FASB issued guidance codified in ASC Topic

606,

Revenue Recognition—Revenue from Contracts with Customers

("ASC

606"),

which amends the guidance in former ASC

605,

Revenue Recognition

, and becomes effective beginning

January

2018.

The Company does not currently expect this standard to have a material effect on its financial statements upon adoption since the Company is not generating revenue at this time.

November

2015,

the FASB issued ASU

2015

17,

Income Taxes: Balance Sheet Classification of Deferred Taxes (Topic

740)

(“ASU

2015

17”),

December

15,

2016,

January

2016,

the FASB issued ASU

2016

01,

Financial Instruments Overall – Recognition and Measurement of Financial Assets and Liabilities (Topic

825

10)

(“ASU

2016

01”),

which provides several updates related to Topic

825

10.

This update applies to all entities that hold financial assets or owe financial liabilities. This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2017,

and interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

February

2016,

the FASB issued ASU

2016

02,

Leases (Topic

842)

(“ASU

2016

02”),

which requires lessees to recognize assets and liabilities for operating leases with lease terms greater than

twelve

2016

is effective for fiscal years beginning after

December

15,

2018,

including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

March

2016,

the FASB issued ASU

2016

06,

Derivatives and Hedging (Topic

815),

Contingent Put and Call Options in Debt Instruments

(“ASU

2016

06”),

2016

is effective for fiscal years beginning after

December

15,

2016,

In Ma

rch

2016,

the FASB issued ASU

2016

09,

Compensation–Stock Compensation (Topic

718),

Improvements to Employee Share-Based Payment Accounting

(“ASU

2016

09”),

2016

is effective for fiscal years beginning after

December

15,

2016,

August

2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows – Classification of Certain Cash Receipts and Cash Payments (Topic

230)

(“ASU

2016

15”),

which addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update applies to all entities that are required to present a statement of cash flows under Topic

230.

This guidance is effective for financial statements issued for fiscal years beginning after

December

15,

2017,

and interim periods within those fiscal years. The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

November

2016,

the FASB issued ASU

2016

18,

Statements of Cash Flows (Topic

320)

– Restricted Cash

(“ASU

2016

15”),

December

15,

2017,

and interim periods within those fiscal years.

The Company is currently evaluating the impact of the adoption of ASU

2016

on its financial statements and disclosures.

Note C - Prepaid Expenses and Other Current Assets (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block]

	December 31,
	2016		2015
Prepaid insurance	$	333	$	290
Other receivables		58		2,375
Other prepaid expenses and current assets		98		93
Total	$	489	$	2,758

Note D - Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Property, Plant and Equipment [Table Text Block]

	December 31,
	2016			2015
Laboratory equipment	$	842		$	530
Furniture and office equipment		733			169
Computers and hardware		231			176
Leasehold improvements		769			6
Total property and equipment		2,575			881
Less: accumulated depreciation and amortization		(605	)		(478	)
Property and equipment, net	$	1,970		$	403

Schedule of Capital Leased Assets [Table Text Block]

	December 31,
	2016			2015
Laboratory equipment	$	271		$	—
Furniture and office equipment		537			94
Leasehold improvements		59			—
Total property and equipment financed under a capital lease agreement		867			94
Less: accumulated depreciation and amortization		(31	)		(22	)
Property and equipment financed under a capital lease agreement, net	$	836		$	72

Property, Plant and Equipment, Useful Life [Table Text Block]

	Useful Life
Asset Category	(in years)
Laboratory equipment		10
Furniture and office equipment		5 - 10
Computers and hardware		3 - 7
Leasehold improvements		9

Note E - Accounts Payable and Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]

	December 31,		December 31,
	2016		2015
Accrued interest	$	2,222	$	698
Accrued banking fees		700		700
Accrued severance		646		—
Accrued payroll		1,024		947
Accounts payable		469		1,252
Other accrued expenses		1,383		1,309
Total	$	6,444	$	4,906

Note G - Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block]

	Capital			Operating
Year Ending December 31,	Leases			Leases
2017	$	214		$	555
2018		208			585
2019		208			569
2020		208			499
2021		127			449
Thereafter		—			1,836
Total minimum lease payments		965		$	4,493
Less: amounts representing interest		(152	)
Total	$	813

Note I - Preferred Stock and Warrants (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Temporary Equity [Table Text Block]

	Shares of
	Series A Preferred			Series B Preferred			Series C Preferred			Series D Preferred			Series D-1 Preferred			Total
Balance, January 1, 2014		9,704,215			6,220,000			18,557,408			—			—			34,481,623
Shares issued upon conversion of 2013 Convertible Notes		—			—			—			5,332,348			—			5,332,348
Shares issued for financing fee to Deerfield		—			—			—			1,923,077			—			1,923,077
Balance, December 31, 2014		9,704,215			6,220,000			18,557,408			7,255,425			—			41,737,048
Issuance of Series D-1 preferred stock		—			—			—			—			3,200,000			3,200,000
Exercise of Series D preferred warrants		—			—			—			3,205			—			3,205
Effect of reverse stock split		(8,410,377	)		(5,390,766	)		(16,083,286	)		(6,290,844	)		(2,784,416	)		(38,959,689	)
Less: Conversion of preferred stock into common stock upon IPO		(1,293,838	)		(829,234	)		(2,474,122	)		(967,786	)		(415,584	)		(5,980,564	)
Balance, December 31, 2015		—			—			—			—			—			—
Balance, December 31, 2016		—			—			—			—			—			—

Note J - Common Stock and Warrants (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Authorized Shares of Common Stock Reserved for Future Issuance [Table Text Block]

	December 31,
	2016		2015
Conversion of Deerfield Convertible Notes		1,751,296		1,991,219
Conversion of 2021 Notes		5,040,914		—
Outstanding awards under equity incentive plans		1,990,260		1,397,511
Outstanding common stock warrants		2,087,477		2,325,383
Possible future issuances under equity incentive plans		1,244,671		1,410,848
Total common shares reserved for future issuance		12,114,618		7,124,961

Schedule of Common Stock Outstanding Roll Forward [Table Text Block]

	Shares of
	Common Stock
Balance at January 1, 2014		2,381,041
Balance at December 31, 2014		2,381,041
Issuance of common stock in connection with the IPO		5,854,545
Conversion of preferred stock to common stock in connection with the IPO		5,980,564
Common stock warrants exercised		270,038
Common stock options exercised		4,766
Balance at December 31, 2015		14,490,954
Common stock warrants exercised		141,095
Common stock options exercised		14,933
Balance at December 31, 2016		14,646,982

Note K - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year ended December 31,
	2016		2015		2014
Research and development	$	1,051	$	610	$	62
General and administrative		3,639		1,759		152
Severance expense		1,910		—		—
	$	6,600	$	2,369	$	214

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	December 31,		December 31,		December 31,
	2016		2015		2014
Risk-free interest rate		1.29% - 1.50%		1.40% - 1.99%		0.91% - 2.70%
Expected term (in years)		5.50 - 6.26		4.33 - 6.25		7.00 - 10.00
Expected volatility		77.38% - 94.78%		68.79% - 86.84%		86.00% - 95.00%
Expected dividend yield		0%		0%		0%

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

						Weighted Average
	Number of			Weighted Average		Remaining Contractual		Aggregate Intrinsic
	Options			Exercise Price		Term (in years)		Value
Outstanding balance at January 1, 2016		1,397,511		$	13.28		8.58	$	9,204,403
Granted		959,375		$	13.31
Exercised		(14,933	)	$	4.78
Canceled, forfeited or expired		(351,693	)	$	11.65
Outsta nding balance at December 31, 2016		1,990,260		$	13.64		8.27	$	26,400
Exercisable at December 31, 2016		637,492		$	10.77		6.78	$	26,400
Vested and expected to vest at December 31, 2016		1,978,260		$	13.62		8.27	$	26,400

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

		Options Outstanding				Options Exercisable
				Weighted Average				Weighted Average
		Number of		Remaining Contractual		Number of		Remaining Contractual
Exercise Price		Shares		Term (in years)		Shares		Term (in years)
$	0.75		12,000		0.50		12,000		0.50
$	3.00		20,666		1.54		20,666		1.54
$	3.80		99,000		9.81		—		—
$	4.65		35,994		2.06		35,994		2.06
$	5.85		298,661		6.26		261,661		6.07
$	6.05		50,000		9.40		—		—
$	8.63		21,306		8.12		10,826		8.15
$	11.00		21,333		8.25		5,333		8.25
$	11.41		88,000		8.41		88,000		8.41
$	12.62		340,000		9.11		—		—
$	13.96		22,500		9.13		—		—
$	16.06		12,000		9.26		—		—
$	16.25		98,750		9.17		—		—
$	16.31		13,500		9.17		—		—
$	16.61		11,250		8.93		2,812		8.93
$	17.93		4,500		9.27		—		—
$	18.10		140,000		9.29		—		—
$	18.29		205,000		8.48		51,250		8.48
$	18.38		54,000		9.28		—		—
$	18.61		32,000		8.65		8,000		8.65
$	19.02		62,000		8.65		54,000		8.65
$	20.45		335,000		8.68		83,750		8.68
$	21.37		6,400		8.69		1,600		8.69
$	22.12		6,400		8.70		1,600		8.70
			1,990,260		8.27		637,492		6.78

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

		Number of Unvested Shares
		December 31,		December 31,
Exercise Price		2016		2015
$	3.80		99,000		—
$	5.85		37,000		97,633
$	6.05		50,000		—
$	8.63		10,480		147,973
$	11.00		16,000		21,333
$	11.41		—		82,035
$	12.62		340,000		—
$	13.96		22,500		—
$	16.06		12,000		—
$	16.25		98,750		—
$	16.31		13,500		—
$	16.61		8,438		11,250
$	17.93		4,500		—
$	18.10		140,000		—
$	18.29		153,750		205,000
$	18.38		54,000		—
$	18.61		24,000		38,400
$	19.02		8,000		62,000
$	20.45		251,250		335,000
$	21.37		4,800		6,400
$	22.12		4,800		6,400
			1,352,768		1,013,424

Note L - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

			Quoted Prices in
	Balance at		Active Markets for		Significant Other		Significant
	December 31,		Identical Assets		Observable Inputs		Unobservable Inputs
	2016		(Level 1)		(Level 2)		(Level 3)
Underwriter Warrant liability	$	16	$	—	$	—	$	16
Deerfield Warrant liability		4,231		—		—		4,231
Embedded Put Option		365		—		—		365
Fundamental change and make-whole interest provisions embedded in 2021 Notes		6		—		—		6
Total liabilities	$	4,618	$	—	$	—	$	4,618
Trading securities:
Certificates of deposit		7,788		7,788		—		—
U.S. Treasury securities		37,066		37,066		—		—
U.S. government-sponsored agency securities		14,349		—		14,349		—
Total assets	$	59,203	$	44,854	$	14,349	$	—

			Quoted Prices in
	Balance at		Active Markets for		Significant Other		Significant
	December 31,		Identical Assets		Observable Inputs		Unobservable Inputs
	2015		(Level 1)		(Level 2)		(Level 3)
Underwriter Warrant liability	$	3,877	$	—	$	—	$	3,877
Deerfield Warrant liability		33,750		—		—		33,750
Embedded Put Option		212		—		—		212
Total liabilities	$	37,839	$	—	$	—	$	37,839
Trading securities:
Certificates of deposit		8,951		8,951		—		—
U.S. Treasury securities		4,996		4,996		—		—
U.S. government-sponsored agency securities		5,055		5,055		—		—
Total assets	$	19,002	$	19,002	$	—	$	—

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	2016			2015
Balance at beginning of period	$	37,839		$	15,966
Reclassification of 2013 warrants to equity		—			(1,110	)
Exercise of warrants		(756	)		(4,293	)
Adjustment to fair value		(32,465	)		27,276
Balance at end of period	$	4,618		$	37,839

Note M - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year ended December 31,
	2016			2015			2014
Federal statutory rate		34.00	%		34.00	%		34.00	%
Effect of:
Change in valuation allowance		(69.31	)		(19.25	)		(32.88	)
Return to provision and deferred true-up		(23.83	)		—			0.36
Change in rate		(14.63	)		—			—
State tax benefit (net of federal)		15.64			4.06			5.96
Warrant liability		68.44			(15.28	)		(9.39	)
State research and development credit		0.09			0.03			0.09
Federal research and development credit		5.65			0.84			3.29
Amortization		(3.15	)		—			—
Conversion feature and put option on 2013 convertible notes		—			(1.68	)		(1.26	)
Interest expense		—			—			0.21
Stock-based compensation		(12.71	)		(1.28	)		—
Other		(0.10	)		(1.42	)		(0.29	)
Federal income tax provision effective rate		0.09	%		0.02	%		0.09	%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,			December 31,			December 31,
	2016			2015			2014
Deferred tax assets relating to:
Net operating loss carryforwards	$	44,984		$	26,617		$	16,390
Research and development tax carryforward		3,166			2,254			1,793
Compensation		715			232			83
Total gross deferred tax assets		48,865			29,103			18,266
Deferred tax liabilities relating to:
Property and equipment		89			80			170
Total gross deferred tax liabilities		89			80			170
Deferred tax assets less liabilities		48,776			29,023			18,096
Valuation allowance		(48,776	)		(29,023	)		(18,096	)
Net deferred tax asset (liability)	$	—		$	—		$	—

Summary of Operating Loss Carryforwards [Table Text Block]

	Net Operating		Research
Year Incurred	Loss Carryforwards		Activities Credit		Expiration
2007	$	454	$	30		2027
2008		1,178		65		2028
2009		3,060		176		2029
2010		3,423		149		2030
2011		9,929		176		2031
2012		—		170		2032
2013		4,353		133		2033
2014		15,819		894		2034
2015		24,189		461		2035
2016		40,959		912		2036
	$	103,364	$	3,166

Note N - Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Year ended December 31,
	2016			2015			2014
Net loss - basic and diluted	$	(16,516	)	$	(54,664	)	$	(24,455	)
Weighted-average number of common shares - basic and diluted		14,597,053			7,368,681			2,381,041
Net loss per share - basic and diluted	$	(1.13	)	$	(7.42	)	$	(10.27	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	December 31,		December 31,		December 31,
	2016		2015		2014
Redeemable convertible preferred stock:
Series A		—		—		1,293,838
Series B		—		—		829,234
Series C		—		—		2,474,122
Series D		—		—		967,359
Total redeemable convertible preferred stock		—		—		5,564,553
Warrants to purchase common stock		2,087,477		2,325,383		595,920
Warrants to purchase Series D preferred stock		—		—		2,066,970
Awards under equity incentive plans		1,990,260		1,397,511		395,185
Deerfield Convertible Notes		1,751,296		1,991,219		1,808,353
2021 Notes		5,040,914		—		—
Total		10,869,947		5,714,113		10,430,981

Note Q - Quarterly Results of Operations (unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Quarterly Financial Information [Table Text Block]

	Three-Months Ended
	Dec 31,			Sep 30,			Jun 30,			Mar 31,			Dec 31,			Sep 30,			Jun 30,			Mar 31,
	2016			2016			2016			2016			2015			2015			2015			2015
Revenue	$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—
Operating expenses:
Research and development		7,963			4,287			4,988			3,234			4,716			4,328			2,768			2,119
General and administrative		2,873			3,104			4,287			3,736			2,566			2,152			3,188			977
Restructuring charges		—			3,010			—			—			—			—			—			—
Total operating expenses		10,836			10,401			9,275			6,970			7,282			6,480			5,956			3,096
Loss from operations		(10,836	)		(10,401	)		(9,275	)		(6,970	)		(7,282	)		(6,480	)		(5,956	)		(3,096	)
Other (expense) income:
Loss on extinguishment of debt		—			—			—			(4,740	)		—			—			—			—
Interest expense related to amortization of debt issuance costs and discount		(391	)		(390	)		(393	)		(442	)		(475	)		(479	)		(477	)		(477	)
Interest expense on principal		(1,445	)		(1,441	)		(1,475	)		(1,150	)		(698	)		(687	)		(654	)		(632	)
Fair value adjustment		2,723			(1,299	)		20,763			10,278			(764	)		(2,089	)		(22,661	)		(1,762	)
Interest and other income		9			98			144			102			15			11			5			—
Total other income (expense)		896			(3,032	)		19,039			4,048			(1,922	)		(3,244	)		(23,787	)		(2,871	)
(Loss) income before income taxes		(9,940	)		(13,433	)		9,764			(2,922	)		(9,204	)		(9,724	)		(29,743	)		(5,967	)
Income tax benefit (expense)		4			19			4			(12	)		1			(20	)		—			(7	)
Net (loss) income	$	(9,936	)	$	(13,414	)	$	9,768		$	(2,934	)	$	(9,203	)	$	(9,744	)	$	(29,743	)	$	(5,974	)

Net (loss) income per share:
Basic	$	(0.68	)	$	(0.92	)	$	0.59		$	(0.20	)	$	(0.64	)	$	(0.68	)	$	(2.45	)	$	(2.50	)
Diluted	$	(0.68	)	$	(0.92	)	$	(0.58	)	$	(0.20	)	$	(0.64	)	$	(0.68	)	$	(2.45	)	$	(2.50	)

Note A - Description of Business and Basis of Presentation (Details Textual)		1 Months Ended		12 Months Ended
	Apr. 02, 2015	May 31, 2015 USD ($) $ / shares shares	Apr. 30, 2015 $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)	Oct. 17, 2016 USD ($)	Oct. 03, 2016 USD ($)
Stockholders' Equity Note, Stock Split, Conversion Ratio	7.5
Proceeds from Issuance Initial Public Offering					$ 59,892,000
Common Stock, Shares Authorized \| shares		250,000,000	250,000,000	250,000,000	250,000,000
Preferred Stock, Shares Authorized \| shares		10,000,000	10,000,000	10,000,000	10,000,000
Common Stock, Par or Stated Value Per Share \| $ / shares		$ 0.0001		$ 0.0001	$ 0.0001
Preferred Stock, Par or Stated Value Per Share \| $ / shares		0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Unamortized Debt Issuance Expense					$ 1,100,000
Other Noncurrent Assets [Member]
Deferred Offering Costs				$ 200,000
Cowen and Company, LLC [Member]
Sale of Stock, Authorized Offering Price							$ 20,000,000
Sale of Stock, Commission Fee							3.00%
Cowen and Company, LLC [Member] \| Maximum [Member]
Sale of Stock, Authorized Offering Price								$ 50,000,000
IPO [Member]
Stock Issued During Period, Shares, New Issues \| shares			5,090,909
Shares Issued, Price Per Share \| $ / shares		$ 11	$ 11
Additional Common Stock Issued During Period		$ 763,636
Proceeds from Issuance Initial Public Offering		59,900,000
Underwriting Discounts and Commissions		4,500,000
Offering Expenses		$ 2,800,000
Stock Issued During Period, Shares, Conversion of Convertible Securities \| shares		5,980,564

Note B - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Trading Securities	$ 50,400,000	$ 10,100,000
Trading Securities, Accumulated Loss	(50,000)	(6,000)
Asset Impairment Charges	0	0	$ 0
Unrecognized Tax Benefits	$ 0	0
Unamortized Debt Issuance Expense		$ 1,100,000
Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment, Useful Life	15 years

Note C - Prepaid Expenses and Other Current Assets - Components of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Prepaid insurance	$ 333	$ 290
Other receivables	58	2,375
Other prepaid expenses and current assets	98	93
Total	$ 489	$ 2,758

Note D - Property and Equipment (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Depreciation, Depletion and Amortization	$ 175,000	$ 84,000	$ 75,000

Note D - Property and Equipment - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property and equipment, gross	$ 2,575	$ 881
Less: accumulated depreciation and amortization	(605)	(478)
Property and equipment, net	1,970	403
Laboratory Equipment [Member]
Property and equipment, gross	842	530
Furniture and Fixtures [Member]
Property and equipment, gross	733	169
Computer and Hardware [Member]
Property and equipment, gross	231	176
Leasehold Improvements [Member]
Property and equipment, gross	$ 769	$ 6

Note D - Property and Equipment - Assets under Capital Leases Included in Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Capital leased assets, gross	$ 867	$ 94
Less: accumulated depreciation and amortization	(31)	(22)
Property and equipment financed under a capital lease agreement, net	836	72
Laboratory Equipment [Member]
Capital leased assets, gross	271
Furniture and Fixtures [Member]
Capital leased assets, gross	537	94
Leasehold Improvements [Member]
Capital leased assets, gross	$ 59

Note D - Property and Equipment - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Minimum [Member]
Property and equipment, useful lives (Year)	3 years
Maximum [Member]
Property and equipment, useful lives (Year)	15 years
Laboratory Equipment [Member]
Property and equipment, useful lives (Year)	10 years
Furniture and Fixtures [Member] \| Minimum [Member]
Property and equipment, useful lives (Year)	5 years
Furniture and Fixtures [Member] \| Maximum [Member]
Property and equipment, useful lives (Year)	10 years
Computer and Hardware [Member] \| Minimum [Member]
Property and equipment, useful lives (Year)	3 years
Computer and Hardware [Member] \| Maximum [Member]
Property and equipment, useful lives (Year)	7 years
Leasehold Improvements [Member]
Property and equipment, useful lives (Year)	9 years

Note E - Accounts Payable and Accrued Expenses - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued interest	$ 2,222	$ 698
Accrued banking fees	700	700
Accrued severance	646
Accrued payroll	1,024	947
Accounts payable	469	1,252
Other accrued expenses	1,383	1,309
Total	$ 6,444	$ 4,906

Note F - Debt Obligations (Details Textual) - USD ($)			12 Months Ended
Note F - Debt Obligations (Details Textual) - USD ($)	Feb. 09, 2016	Jun. 02, 2014	Dec. 31, 2016	Jun. 30, 2016	Apr. 30, 2015	Dec. 31, 2013
Series D Redeemable Convertible Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					15,499,324	1,079,453
2021 Notes [Member]
Debt Instrument, Convertible, Conversion Price	$ 17.11
Debt Instrument, Face Amount	$ 86,250,000
Debt Instrument, Interest Rate, Stated Percentage	5.50%
Proceeds from Debt, Net of Issuance Costs	$ 82,800,000
Repayments of Long-term Debt	$ 18,600,000
Debt Conversion, Converted Instrument, Shares Issued	58.4454
Debt Conversion, Original Debt, Amount	$ 1,000
Debt Instrument Repurchase Price Equal to Percentage of Principal Amount	100.00%
Debt Instrument, Sinking Fund Payment	$ 0
Deerfield Facility Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 60,000,000
Line of Credit Facility, Interest Rate at Period End		9.75%
Debt Covenant, Debt Financing Restriction		$ 750,000
Deerfield Facility Agreement [Member] \| IPO [Member]
Reclassification of Common Stock Shares		256,410
Deerfield Facility Agreement [Member] \| Deerfield Warrant [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.78
Deerfield Facility Agreement [Member] \| Deerfield Warrant [Member] \| IPO [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		1,923,077
Deerfield Facility Agreement [Member] \| Series D Redeemable Convertible Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		14,423,076
Own-share Lending Arrangement, Shares, Issued		1,923,077
Mandatorily Redeemable Preferred Stock, Fair Value Disclosure		$ 1,500,000
Deerfield Facility Agreement [Member] \| Term Notes [Member]
Proceeds from Secured Notes Payable		15,000,000
Deerfield Facility Agreement [Member] \| Deerfield Convertible Notes [Member]
Proceeds from Secured Notes Payable		$ 10,000,000
Debt Instrument, Convertible, Conversion Price		$ 5.85
Third Line of Credit Agreement [Member] \| City National Bank of Florida [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 1,100,000
Line of Credit Facility, Remaining Borrowing Capacity			$ 400,000
Long-term Line of Credit			$ 0
Third Line of Credit Agreement [Member] \| City National Bank of Florida [Member] \| Prime Rate [Member]
Debt Instrument, Interest Rate, Stated Percentage			2.77%
Debt Instrument, Basis Spread on Variable Rate			2.00%

Note G - Commitments and Contingencies (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingency Accrual		$ 0	$ 20,000
Operating and Capital Leases, Rent Expense, Net		$ 600,000	$ 300,000	$ 200,000
Capital Lease One [Member]
Capital Lease, Interest Rate		7.19%
Capital Lease Two [Member]
Capital Lease, Interest Rate		8.05%
Iowa [Member]
Lessor Leasing Arrangements, Operating Leases, Renewal Term		1 year
Florida [Member]
Lessor Leasing Arrangements, Operating Leases, Renewal Term	5 years
North Carolina [Member]
Lessor Leasing Arrangements, Operating Leases, Renewal Term		3 years

Note G - Commitment and Contingencies - Future Minimum Lease Payments under Capital Leases and Non-cancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2016 USD ($)
2017	$ 214
2017	555
2018	208
2018	585
2019	208
2019	569
2020	208
2020	499
2021	127
2021	449
Thereafter
Thereafter	1,836
Total minimum lease payments	965
Total minimum lease payments	4,493
Less: amounts representing interest	(152)
Total	$ 813

Note H - Supply Arrangement (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Number of Manufacturing Arrangement	1
Supply Arrangement, Automatic Renewal Period	2 years
Supply Arrangement, Period of Prior Notice	1 year
Supply Arrangement Expense	$ 0	$ 0	$ 0

Note I - Preferred Stock and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended			12 Months Ended
	Jun. 02, 2014	May 31, 2015	Apr. 30, 2015	Feb. 28, 2015	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2016
Preferred Stock, Shares Authorized		10,000,000	10,000,000		10,000,000		10,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.0001	$ 0.0001		$ 0.0001		$ 0.0001
Conversion of Preferred Stock to Common Stock Upon Initial Public Offering Shares					5,980,564
Preferred Stock, Shares Outstanding					0		0
2013 Warrants [Member]
Class of Warrant or Right Issued						1,079,453
Deerfield Warrant [Member]
Class of Warrant or Right Issued	14,423,076
Convertible Notes Payable [Member]
Debt Instrument, Face Amount						$ 3.8
Series D-1 Redeemable Convertible Preferred Stock [Member]
Conversion of Preferred Stock to Common Stock Upon Initial Public Offering Shares					415,584
Series D-1 Redeemable Convertible Preferred Stock [Member] \| Cowen KP Investment LLC [Member]
Temporary Equity Shares Issuance				3,200,000
Sale of Stock, Price Per Share				$ 1.25
Proceeds from Issuance of Redeemable Convertible Preferred Stock				$ 4.0
Conversion of Preferred Stock to Common Stock Upon Initial Public Offering Shares				415,584
Series D Redeemable Convertible Preferred Stock [Member]
Conversion of Preferred Stock to Common Stock Upon Initial Public Offering Shares					967,786
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			15,499,324			1,079,453
IPO [Member]
Stock Issued During Period, Shares, Conversion of Convertible Securities		5,980,564
Common Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			2,066,543			143,466
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 5.85
Common Stock [Member] \| Deerfield Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	1,923,077
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5.85
Common Stock [Member] \| IPO [Member]
Stock Issued During Period, Shares, Conversion of Convertible Securities			5,980,564		5,980,564

Note I - Preferred Stock and Warrants - Summary of Redeemable Convertible Preferred Stock Activity (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2013
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(5,980,564)
Scenario, Previously Reported [Member]
Balance (in shares)		41,737,048		34,481,623
Stock Issued During Period, Shares, Conversion of Convertible Securities		5,332,348
Shares issued for financing fee to Deerfield (in shares)		1,923,077
Temporary Equity Shares Issuance	3,200,000
Exercise of Series D preferred warrants (in shares)	3,205
Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(38,959,689)
Series A Redeemable Convertible Preferred Stock [Member]
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(1,293,838)
Series A Redeemable Convertible Preferred Stock [Member] \| Scenario, Previously Reported [Member]
Balance (in shares)		9,704,215		9,704,215
Stock Issued During Period, Shares, Conversion of Convertible Securities
Shares issued for financing fee to Deerfield (in shares)
Temporary Equity Shares Issuance
Exercise of Series D preferred warrants (in shares)
Series A Redeemable Convertible Preferred Stock [Member] \| Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(8,410,377)
Series B Redeemable Convertible Preferred Stock [Member]
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(829,234)
Series B Redeemable Convertible Preferred Stock [Member] \| Scenario, Previously Reported [Member]
Balance (in shares)		6,220,000		6,220,000
Stock Issued During Period, Shares, Conversion of Convertible Securities
Shares issued for financing fee to Deerfield (in shares)
Temporary Equity Shares Issuance
Exercise of Series D preferred warrants (in shares)
Series B Redeemable Convertible Preferred Stock [Member] \| Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(5,390,766)
Series C Redeemable Convertible Preferred Stock [Member]
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(2,474,122)
Series C Redeemable Convertible Preferred Stock [Member] \| Scenario, Previously Reported [Member]
Balance (in shares)		18,557,408		18,557,408
Stock Issued During Period, Shares, Conversion of Convertible Securities
Shares issued for financing fee to Deerfield (in shares)
Temporary Equity Shares Issuance
Exercise of Series D preferred warrants (in shares)
Series C Redeemable Convertible Preferred Stock [Member] \| Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(16,083,286)
Series D Redeemable Convertible Preferred Stock [Member]
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(967,786)
Series D Redeemable Convertible Preferred Stock [Member] \| Scenario, Previously Reported [Member]
Balance (in shares)		7,255,425
Stock Issued During Period, Shares, Conversion of Convertible Securities		5,332,348
Shares issued for financing fee to Deerfield (in shares)		1,923,077
Temporary Equity Shares Issuance
Exercise of Series D preferred warrants (in shares)	3,205
Series D Redeemable Convertible Preferred Stock [Member] \| Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(6,290,844)
Series D-1 Redeemable Convertible Preferred Stock [Member]
Balance (in shares)
Less: Conversion of preferred stock into common stock upon IPO (in shares)	(415,584)
Series D-1 Redeemable Convertible Preferred Stock [Member] \| Scenario, Previously Reported [Member]
Balance (in shares)
Stock Issued During Period, Shares, Conversion of Convertible Securities
Shares issued for financing fee to Deerfield (in shares)
Temporary Equity Shares Issuance	3,200,000
Exercise of Series D preferred warrants (in shares)
Series D-1 Redeemable Convertible Preferred Stock [Member] \| Restatement Adjustment [Member]
Effect of reverse stock split (in shares)	(2,784,416)

Note J - Common Stock and Warrants (Details Textual) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 31, 2015	Apr. 30, 2015	Dec. 31, 2013	Dec. 31, 2012
Common Stock, Shares Authorized	250,000,000	250,000,000		250,000,000	250,000,000
Common Stock, Shares, Issued	14,646,982	14,490,954
Common Stock Issued During Period from Warrants Exercised	141,095	270,038	0
Common Stock, Shares, Outstanding	14,646,982	14,490,954	2,381,041			2,381,041
Private Placement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights							595,920

Note J - Common Stock and Warrants - Reserved Authorized Shares of Common Stock for Future Issuance (Details) - shares	Dec. 31, 2016	Dec. 31, 2015
Common shares reserved for future issuance (in shares)	12,114,618	7,124,961
Warrant [Member]
Common shares reserved for future issuance (in shares)	2,087,477	2,325,383
Stock Compensation Plan [Member]
Common shares reserved for future issuance (in shares)	1,990,260	1,397,511
Possible Future Issuances Under Equity Incentive Plans [Member]
Common shares reserved for future issuance (in shares)	1,244,671	1,410,848
2021 Notes [Member]
Common shares reserved for future issuance (in shares)	5,040,914
Convertible Notes Payable [Member]
Common shares reserved for future issuance (in shares)	1,751,296	1,991,219

Note J - Common Stock and Warrants - Common Stock Activity (Details) - shares	1 Months Ended		12 Months Ended
	May 31, 2015	Apr. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance (in shares)			14,490,954	2,381,041	2,381,041
Balance (in shares)			14,646,982	14,490,954	2,381,041
Common stock warrants exercised (in shares)			141,095	270,038	0
Common stock options exercised (in shares)			14,933	4,766	0
IPO [Member]
Issuance of common stock in connection with the IPO (in shares)		5,090,909
Conversion of preferred stock to common stock in connection with the IPO (in shares)	5,980,564
Common Stock [Member] \| IPO [Member]
Issuance of common stock in connection with the IPO (in shares)				5,854,545
Conversion of preferred stock to common stock in connection with the IPO (in shares)		5,980,564		5,980,564

Note K - Stock-based Compensation (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	14,933	4,766	0
Stock Issued During Period, Value, Stock Options Exercised	$ 71,000	$ 28,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 169,000	$ 54,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value	$ 9.25	$ 10.63	$ 4.50
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 5,400,000	$ 1,100,000	$ 200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 10,600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 313 days
Allocated Share-based Compensation Expense	$ 6,600,000	$ 2,369,000	214,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares	13,333	163,998
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	$ 1,051,000	$ 610,000	62,000
General and Administrative Expense [Member]
Allocated Share-based Compensation Expense	3,639,000	1,759,000	$ 152,000
Performance Shares [Member] \| Research and Development Expense [Member]
Allocated Share-based Compensation Expense	$ 44,000	200,000
Performance Shares [Member] \| General and Administrative Expense [Member]
Allocated Share-based Compensation Expense		$ 700,000
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	2,846,304
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Reserved for Issuance, Incremental Percentage of Capital Stock Outstanding	4.00%
Increase in Common Stock Reserved for Issuance	585,879

Note K - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock based compensation expense	$ 6,600	$ 2,369	$ 214
Research and Development Expense [Member]
Stock based compensation expense	1,051	610	62
General and Administrative Expense [Member]
Stock based compensation expense	3,639	1,759	152
Severance Expense [Member]
Stock based compensation expense	$ 1,910

Note K - Stock-based Compensation - Black-Scholes Option Pricing Model (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Expected dividend yield	0.00%	0.00%	0.00%
Minimum [Member]
Risk-free interest rate	1.29%	1.40%	0.91%
Expected term (in years) (Year)	5 years 182 days	4 years 120 days	7 years
Expected volatility	77.38%	68.79%	86.00%
Maximum [Member]
Risk-free interest rate	1.50%	1.99%	2.70%
Expected term (in years) (Year)	6 years 94 days	6 years 91 days	10 years
Expected volatility	94.78%	86.84%	95.00%

Note K - Stock-based Compensation - Schedule of Stock Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Outstanding, number of options (in shares)	1,397,511
Outstanding, weighted average exercise price (in dollars per share)	$ 13.28
Outstanding, weighted average remaining contractual term (Year)	8 years 98 days	8 years 211 days
Outstanding, aggregate intrinsic value	$ 26,400	$ 9,204,403
Granted (in shares)	959,375
Granted (in dollars per share)	$ 13.31
Exercised (in shares)	(14,933)	(4,766)	0
Exercised (in dollars per share)	$ 4.78
Canceled, forfeited or expired (in shares)	(351,693)
Canceled, forfeited or expired (in dollars per share)	$ 11.65
Outstanding, number of options (in shares)	1,990,260	1,397,511
Outstanding, weighted average exercise price (in dollars per share)	$ 13.64	$ 13.28
Exercisable, number of options (in shares)	637,492
Exercisable, weighted average exercise price (in dollars per share)	$ 10.77
Exercisable, weighted average remaining contractual term (Year)	6 years 284 days
Exercisable, aggregate intrinsic value	$ 26,400
Vested and expected to vest, number of options (in shares)	1,978,260
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 13.62
Vested and expected to vest, weighted average remaining contractual term (Year)	8 years 98 days
Vested and expected to vest, aggregate intrinsic value	$ 26,400

Note K - Stock-based Compensation - Information Regarding Currently Outstanding and Exercisable Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Exercised (in dollars per share)	$ 4.78
Options outstanding, number of shares (in shares)	1,990,260	1,397,511
Outstanding, weighted average remaining contractual term (Year)	8 years 98 days	8 years 211 days
Exercisable, number of options (in shares)	637,492
Exercisable, weighted average remaining contractual term (Year)	6 years 284 days
Exercise Price Range One [Member]
Exercised (in dollars per share)	$ 0.75
Options outstanding, number of shares (in shares)	12,000
Outstanding, weighted average remaining contractual term (Year)	182 days
Exercisable, number of options (in shares)	12,000
Exercisable, weighted average remaining contractual term (Year)	182 days
Exercise Price Range Two [Member]
Exercised (in dollars per share)	$ 3
Options outstanding, number of shares (in shares)	20,666
Outstanding, weighted average remaining contractual term (Year)	1 year 197 days
Exercisable, number of options (in shares)	20,666
Exercisable, weighted average remaining contractual term (Year)	1 year 197 days
Exercise Price Range Three [Member]
Exercised (in dollars per share)	$ 3.80
Options outstanding, number of shares (in shares)	99,000
Outstanding, weighted average remaining contractual term (Year)	9 years 295 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Four [Member]
Exercised (in dollars per share)	$ 4.65
Options outstanding, number of shares (in shares)	35,994
Outstanding, weighted average remaining contractual term (Year)	2 years 21 days
Exercisable, number of options (in shares)	35,994
Exercisable, weighted average remaining contractual term (Year)	2 years 21 days
Exercise Price Range Five [Member]
Exercised (in dollars per share)	$ 5.85
Options outstanding, number of shares (in shares)	298,661
Outstanding, weighted average remaining contractual term (Year)	6 years 94 days
Exercisable, number of options (in shares)	261,661
Exercisable, weighted average remaining contractual term (Year)	6 years 25 days
Exercise Price Range Six [Member]
Exercised (in dollars per share)	$ 6.05
Options outstanding, number of shares (in shares)	50,000
Outstanding, weighted average remaining contractual term (Year)	9 years 146 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Seven [Member]
Exercised (in dollars per share)	$ 8.63
Options outstanding, number of shares (in shares)	21,306
Outstanding, weighted average remaining contractual term (Year)	8 years 43 days
Exercisable, number of options (in shares)	10,826
Exercisable, weighted average remaining contractual term (Year)	8 years 54 days
Exercise Price Range Eight [Member]
Exercised (in dollars per share)	$ 11
Options outstanding, number of shares (in shares)	21,333
Outstanding, weighted average remaining contractual term (Year)	8 years 91 days
Exercisable, number of options (in shares)	5,333
Exercisable, weighted average remaining contractual term (Year)	8 years 91 days
Exercise Price Range Nine [Member]
Exercised (in dollars per share)	$ 11.41
Options outstanding, number of shares (in shares)	88,000
Outstanding, weighted average remaining contractual term (Year)	8 years 149 days
Exercisable, number of options (in shares)	88,000
Exercisable, weighted average remaining contractual term (Year)	8 years 149 days
Exercise Price Range Ten [Member]
Exercised (in dollars per share)	$ 12.62
Options outstanding, number of shares (in shares)	340,000
Outstanding, weighted average remaining contractual term (Year)	9 years 40 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Eleven [Member]
Exercised (in dollars per share)	$ 13.96
Options outstanding, number of shares (in shares)	22,500
Outstanding, weighted average remaining contractual term (Year)	9 years 47 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Twelve [Member]
Exercised (in dollars per share)	$ 16.06
Options outstanding, number of shares (in shares)	12,000
Outstanding, weighted average remaining contractual term (Year)	9 years 94 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Thirteen [Member]
Exercised (in dollars per share)	$ 16.25
Options outstanding, number of shares (in shares)	98,750
Outstanding, weighted average remaining contractual term (Year)	9 years 62 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Fourteen [Member]
Exercised (in dollars per share)	$ 16.31
Options outstanding, number of shares (in shares)	13,500
Outstanding, weighted average remaining contractual term (Year)	9 years 62 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Fifteen [Member]
Exercised (in dollars per share)	$ 16.61
Options outstanding, number of shares (in shares)	11,250
Outstanding, weighted average remaining contractual term (Year)	8 years 339 days
Exercisable, number of options (in shares)	2,812
Exercisable, weighted average remaining contractual term (Year)	8 years 339 days
Exercise Price Range Sixteen [Member]
Exercised (in dollars per share)	$ 17.93
Options outstanding, number of shares (in shares)	4,500
Outstanding, weighted average remaining contractual term (Year)	9 years 98 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Seventeen [Member]
Exercised (in dollars per share)	$ 18.10
Options outstanding, number of shares (in shares)	140,000
Outstanding, weighted average remaining contractual term (Year)	9 years 105 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Eighteen [Member]
Exercised (in dollars per share)	$ 18.29
Options outstanding, number of shares (in shares)	205,000
Outstanding, weighted average remaining contractual term (Year)	8 years 175 days
Exercisable, number of options (in shares)	51,250
Exercisable, weighted average remaining contractual term (Year)	8 years 175 days
Exercise Price Range Nineteen [Member]
Exercised (in dollars per share)	$ 18.38
Options outstanding, number of shares (in shares)	54,000
Outstanding, weighted average remaining contractual term (Year)	9 years 102 days
Exercisable, number of options (in shares)
Exercisable, weighted average remaining contractual term (Year)
Exercise Price Range Twenty [Member]
Exercised (in dollars per share)	$ 18.61
Options outstanding, number of shares (in shares)	32,000
Outstanding, weighted average remaining contractual term (Year)	8 years 237 days
Exercisable, number of options (in shares)	8,000
Exercisable, weighted average remaining contractual term (Year)	8 years 237 days
Exercise Price Range Twenty One [Member]
Exercised (in dollars per share)	$ 19.02
Options outstanding, number of shares (in shares)	62,000
Outstanding, weighted average remaining contractual term (Year)	8 years 237 days
Exercisable, number of options (in shares)	54,000
Exercisable, weighted average remaining contractual term (Year)	8 years 237 days
Exercise Price Range Twenty Two [Member]
Exercised (in dollars per share)	$ 20.45
Options outstanding, number of shares (in shares)	335,000
Outstanding, weighted average remaining contractual term (Year)	8 years 248 days
Exercisable, number of options (in shares)	83,750
Exercisable, weighted average remaining contractual term (Year)	8 years 248 days
Exercise Price Range Twenty Three [Member]
Exercised (in dollars per share)	$ 21.37
Options outstanding, number of shares (in shares)	6,400
Outstanding, weighted average remaining contractual term (Year)	8 years 251 days
Exercisable, number of options (in shares)	1,600
Exercisable, weighted average remaining contractual term (Year)	8 years 251 days
Exercise Price Range Twenty Four [Member]
Exercised (in dollars per share)	$ 22.12
Options outstanding, number of shares (in shares)	6,400
Outstanding, weighted average remaining contractual term (Year)	8 years 255 days
Exercisable, number of options (in shares)	1,600
Exercisable, weighted average remaining contractual term (Year)	8 years 255 days

Note K - Stock-based Compensation - Nonvested Stock Option Awards (Details) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Exercise price (in dollars per share)
Number of unvested shares (in shares)	1,352,768	1,013,424
Exercise Price Range One [Member]
Exercise price (in dollars per share)	$ 3.80
Number of unvested shares (in shares)	99,000
Exercise Price Range Two [Member]
Exercise price (in dollars per share)	$ 5.85
Number of unvested shares (in shares)	37,000	97,633
Exercise Price Range Three [Member]
Exercise price (in dollars per share)	$ 6.05
Number of unvested shares (in shares)	50,000
Exercise Price Range Four [Member]
Exercise price (in dollars per share)	$ 8.63
Number of unvested shares (in shares)	10,480	147,973
Exercise Price Range Five [Member]
Exercise price (in dollars per share)	$ 11
Number of unvested shares (in shares)	16,000	21,333
Exercise Price Range Six [Member]
Exercise price (in dollars per share)	$ 11.41
Number of unvested shares (in shares)		82,035
Exercise Price Range Seven [Member]
Exercise price (in dollars per share)	$ 12.62
Number of unvested shares (in shares)	340,000
Exercise Price Range Eight [Member]
Exercise price (in dollars per share)	$ 13.96
Number of unvested shares (in shares)	22,500
Exercise Price Range Nine [Member]
Exercise price (in dollars per share)	$ 16.06
Number of unvested shares (in shares)	12,000
Exercise Price Range Ten [Member]
Exercise price (in dollars per share)	$ 16.25
Number of unvested shares (in shares)	98,750
Exercise Price Range Eleven [Member]
Exercise price (in dollars per share)	$ 16.31
Number of unvested shares (in shares)	13,500
Exercise Price Range Twelve [Member]
Exercise price (in dollars per share)	$ 16.61
Number of unvested shares (in shares)	8,438	11,250
Exercise Price Range Thirteen [Member]
Exercise price (in dollars per share)	$ 17.93
Number of unvested shares (in shares)	4,500
Exercise Price Range Fourteen [Member]
Exercise price (in dollars per share)	$ 18.10
Number of unvested shares (in shares)	140,000
Exercise Price Range Fifteen [Member]
Exercise price (in dollars per share)	$ 18.29
Number of unvested shares (in shares)	153,750	205,000
Exercise Price Range Sixteen [Member]
Exercise price (in dollars per share)	$ 18.38
Number of unvested shares (in shares)	54,000
Exercise Price Range Seventeen [Member]
Exercise price (in dollars per share)	$ 18.61
Number of unvested shares (in shares)	24,000	38,400
Exercise Price Range Eighteen [Member]
Exercise price (in dollars per share)	$ 19.02
Number of unvested shares (in shares)	8,000	62,000
Exercise Price Range Nineteen [Member]
Exercise price (in dollars per share)	$ 20.45
Number of unvested shares (in shares)	251,250	335,000
Exercise Price Range Twenty [Member]
Exercise price (in dollars per share)	$ 21.37
Number of unvested shares (in shares)	4,800	6,400
Exercise Price Range Twenty One [Member]
Exercise price (in dollars per share)	$ 22.12
Number of unvested shares (in shares)	4,800	6,400

Note L - Fair Value of Financial Instruments (Details Textual) - Fair Value, Inputs, Level 3 [Member] - Deerfield Facility Agreement [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deerfield Convertible Notes [Member]
Long-term Debt, Fair Value	$ 10.2	$ 42.0
Term Notes [Member]
Long-term Debt, Fair Value	$ 46.3

Note L - Fair Value of Financial Instruments - Reconciliation of Beginning and Ending Balances for Derivative and Warrant Liability Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Balance at beginning of period	$ 37,839	$ 15,966
Reclassification of 2013 warrants to equity		(1,110)
Exercise of warrants	(756)	(4,293)
Adjustment to fair value	(32,465)	27,276
Balance at end of period	$ 4,618	$ 37,839

Note M - Income Taxes (Details Textual) - USD ($)	3 Months Ended								12 Months Ended
Note M - Income Taxes (Details Textual) - USD ($)	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
State and Local Income Tax Expense (Benefit), Continuing Operations									$ 15,000	$ 15,000	$ 22,000
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ (9,940,000)	$ (13,433,000)	$ 9,764,000	$ (2,922,000)	$ (9,204,000)	$ (9,724,000)	$ (29,743,000)	$ (5,967,000)	(16,531,000)	$ (54,638,000)	$ (24,477,000)
Operating Loss Carryforwards	103,364,000								103,364,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 108,600,000								$ 108,600,000
Operating Loss Carryforwards, Expiration, Beginning Year									2027
Operating Loss Carryforwards, Expiration, Ending Year									2036

Note M - Income Taxes - Schedule of Reconciliation of Difference Between Benefit for Income Taxes and Income Taxes at Statutory U.S. Federal Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal statutory rate	34.00%	34.00%	34.00%
Change in valuation allowance	(69.31%)	(19.25%)	(32.88%)
Return to provision and deferred true-up	(23.83%)		0.36%
Change in rate	(14.63%)
State tax benefit (net of federal)	15.64%	4.06%	5.96%
Warrant liability	68.44%	(15.28%)	(9.39%)
Amortization	(3.15%)
Conversion feature and put option on 2013 convertible notes		(1.68%)	(1.26%)
Interest expense			0.21%
Stock-based compensation	(12.71%)	(1.28%)
Other	(0.10%)	(1.42%)	(0.29%)
Federal income tax provision effective rate	0.09%	0.02%	0.09%
State and Local Jurisdiction [Member]
State research and development credit	0.09%	0.03%	0.09%
Domestic Tax Authority [Member]
State research and development credit	5.65%	0.84%	3.29%

Note M - Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net operating loss carryforwards	$ 44,984	$ 26,617	$ 16,390
Research and development tax carryforward	3,166	2,254	1,793
Compensation	715	232	83
Total gross deferred tax assets	48,865	29,103	18,266
Property and equipment	89	80	170
Total gross deferred tax liabilities	89	80	170
Deferred tax assets less liabilities	48,776	29,023	18,096
Valuation allowance	(48,776)	(29,023)	(18,096)
Net deferred tax asset (liability)

Note M - Income Taxes - Federal Net Operating Loss Carryforward and Research Activities Credit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Operating Loss Carryforwards	$ 103,364
Research Activities Credit	3,166	$ 2,254	$ 1,793
Tax Year 2007 [Member]
Net Operating Loss Carryforwards	454
Research Activities Credit	$ 30
Expiration	2027
Tax Year 2008 [Member]
Net Operating Loss Carryforwards	$ 1,178
Research Activities Credit	$ 65
Expiration	2028
Tax Year 2009 [Member]
Net Operating Loss Carryforwards	$ 3,060
Research Activities Credit	$ 176
Expiration	2029
Tax Year 2010 [Member]
Net Operating Loss Carryforwards	$ 3,423
Research Activities Credit	$ 149
Expiration	2030
Tax Year 2011 [Member]
Net Operating Loss Carryforwards	$ 9,929
Research Activities Credit	$ 176
Expiration	2031
Tax Year 2012 [Member]
Net Operating Loss Carryforwards
Research Activities Credit	$ 170
Expiration	2032
Tax Year 2013 [Member]
Net Operating Loss Carryforwards	$ 4,353
Research Activities Credit	$ 133
Expiration	2033
Tax Year 2014 [Member]
Net Operating Loss Carryforwards	$ 15,819
Research Activities Credit	$ 894
Expiration	2034
Tax Year 2015 [Member]
Net Operating Loss Carryforwards	$ 24,189
Research Activities Credit	$ 461
Expiration	2035
Tax Year 2016 [Member]
Net Operating Loss Carryforwards	$ 40,959
Research Activities Credit	$ 912
Expiration	2036

Note N - Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss and Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss - basic and diluted	$ (9,936)	$ (13,414)	$ 9,768	$ (2,934)	$ (9,203)	$ (9,744)	$ (29,743)	$ (5,974)	$ (16,516)	$ (54,664)	$ (24,455)
Weighted-average number of common shares - basic and diluted (in shares)									14,597,053	7,368,681	2,381,041
Net loss per share - basic and diluted (in dollars per share)									$ (1.13)	$ (7.42)	$ (10.27)

Note N - Net Loss Per Share - Anti-dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Series A (in shares)	10,869,947	5,714,113	10,430,981
Warrants to Purchase Common Stock [Member]
Series A (in shares)	2,087,477	2,325,383	595,920
Deerfield Warrant to Purchase Series D Preferred Stock [Member]
Series A (in shares)			2,066,970
Stock Compensation Plan [Member]
Series A (in shares)	1,990,260	1,397,511	395,185
Convertible Debt Securities [Member]
Series A (in shares)	1,751,296	1,991,219	1,808,353
2021 Notes [Member]
Series A (in shares)	5,040,914
Series A Redeemable Convertible Preferred Stock [Member]
Series A (in shares)			1,293,838
Series B Redeemable Convertible Preferred Stock [Member]
Series A (in shares)			829,234
Series C Redeemable Convertible Preferred Stock [Member]
Series A (in shares)			2,474,122
Series D Redeemable Convertible Preferred Stock [Member]
Series A (in shares)			967,359
Redeemable Convertible Preferred Stock [Member]
Series A (in shares)			5,564,553

Note O - Severance Expense (Details Textual) $ in Thousands	3 Months Ended								12 Months Ended
Note O - Severance Expense (Details Textual) $ in Thousands	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Restructuring and Related Cost, Number of Positions Eliminated									3
Restructuring Charges		$ 3,010
Allocated Share-based Compensation Expense									$ 6,600	$ 2,369	$ 214
Severance Expense [Member]
Allocated Share-based Compensation Expense									1,910
Employee Severance [Member] \| Accounts Payable and Accrued Liabilities [Member]
Restructuring Reserve	$ 600								600
Employee Severance [Member] \| Severance Expense [Member]
Restructuring Charges									1,100
Allocated Share-based Compensation Expense									$ 1,900

Note P - Employee Benefit Plan (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirement Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 213,000	$ 113,000	$ 69,000
Profit Sharing Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	0.00%	0.00%	0.00%

Note Q - Quarterly Results of Operations (unaudited) - Schedule of Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Operating expenses:
Research and development	7,963	4,287	4,988	3,234	4,716	4,328	2,768	2,119	20,472	13,931	11,917
General and administrative	2,873	3,104	4,287	3,736	2,566	2,152	3,188	977	14,000	8,883	4,526
Restructuring Charges		3,010
Total operating expenses	10,836	10,401	9,275	6,970	7,282	6,480	5,956	3,096	37,482	22,814	16,443
Loss from operations	(10,836)	(10,401)	(9,275)	(6,970)	(7,282)	(6,480)	(5,956)	(3,096)	(37,482)	(22,814)	(16,443)
Other income (expense):
Loss on extinguishment of debt				(4,740)					(4,740)		1,900
Interest expense related to amortization of debt issuance costs and discount	(391)	(390)	(393)	(442)	(475)	(479)	(477)	(477)	(1,616)	(1,909)	(1,114)
Interest expense on principal	(1,445)	(1,441)	(1,475)	(1,150)	(698)	(687)	(654)	(632)	(5,511)	(2,671)	(1,605)
Fair value adjustment	2,723	(1,299)	20,763	10,278	(764)	(2,089)	(22,661)	(1,762)	32,465	(27,276)	(7,223)
Interest and other income	9	98	144	102	15	11	5		353	32	8
Total other income (expense)	896	(3,032)	19,039	4,048	(1,922)	(3,244)	(23,787)	(2,871)	20,951	(31,824)	(8,034)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(9,940)	(13,433)	9,764	(2,922)	(9,204)	(9,724)	(29,743)	(5,967)	(16,531)	(54,638)	(24,477)
Income tax benefit (expense)	4	19	4	(12)	1	(20)		(7)	15	(26)	22
Net loss - basic and diluted	$ (9,936)	$ (13,414)	$ 9,768	$ (2,934)	$ (9,203)	$ (9,744)	$ (29,743)	$ (5,974)	$ (16,516)	$ (54,664)	$ (24,455)
Net loss per share:
Basic (in dollars per share)	$ (0.68)	$ (0.92)	$ 0.59	$ (0.20)	$ (0.64)	$ (0.68)	$ (2.45)	$ (2.50)
Diluted (in dollars per share)	$ (0.68)	$ (0.92)	$ (0.58)	$ (0.20)	$ (0.64)	$ (0.68)	$ (2.45)	$ (2.50)

Note L - Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial liabilities measured at fair value on recurring basis	$ 4,618	$ 37,839
Financial assets measured at fair value on recurring basis	59,203	19,002
Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis	7,788	8,951
US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis	37,066	4,996
US Government Corporations and Agencies Securities [Member]
Financial assets measured at fair value on recurring basis	14,349	5,055
Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Financial assets measured at fair value on recurring basis	44,854	19,002
Fair Value, Inputs, Level 1 [Member] \| Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis	7,788	8,951
Fair Value, Inputs, Level 1 [Member] \| US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis	37,066	4,996
Fair Value, Inputs, Level 1 [Member] \| US Government Corporations and Agencies Securities [Member]
Financial assets measured at fair value on recurring basis		5,055
Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Financial assets measured at fair value on recurring basis	14,349
Fair Value, Inputs, Level 2 [Member] \| Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 2 [Member] \| US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 2 [Member] \| US Government Corporations and Agencies Securities [Member]
Financial assets measured at fair value on recurring basis	14,349
Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	4,618	37,839
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member] \| Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member] \| US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member] \| US Government Corporations and Agencies Securities [Member]
Financial assets measured at fair value on recurring basis
Underwriter Warrant Liability [Member]
Financial liabilities measured at fair value on recurring basis	16	3,877
Underwriter Warrant Liability [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Underwriter Warrant Liability [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Underwriter Warrant Liability [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	16	3,877
Deerfield Warrant Liability [Member]
Financial liabilities measured at fair value on recurring basis	4,231	33,750
Deerfield Warrant Liability [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Deerfield Warrant Liability [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Deerfield Warrant Liability [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	4,231	33,750
Embedded Put Option [Member]
Financial liabilities measured at fair value on recurring basis	365	212
Embedded Put Option [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Put Option [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Put Option [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	365	$ 212
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member]
Financial liabilities measured at fair value on recurring basis	6
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	$ 6