Note E - Preferred Stock and Warrants	6 Months Ended
Jun. 30, 2016
Notes to Financial Statements
Preferred Stock [Text Block]	E. Preferred Stock and Warrants Authorized, Issued, and Outstanding Preferred Stock In 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 Comp any 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 June 30, 2016, the Company had 10,000,000 shares of authorized and undesignated preferred stock and did not have any preferred stock outstanding. Series D-1 Redeemable Convertible Preferred Stock In February 2015, the Company entered int o 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-1 redeemable convertible preferred stock (“Series D-1 Preferred”) for $1.25 per share, or an aggregate of $4 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, and as of June 30, 2016, warrants to purchase 15,499,324 shares of Series D Preferred 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. 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 2, 2019, or upon a liquidation event. On June 2, 2014, pursuant to the terms of the Deerfield Facility Agreement, the Company issued the Deerfield Warrant to purchase 14,423,076 shares of Series D Preferred. 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 2, 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 liability and stated at fair value a t 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 determined that the 2013 Warrants should be marked to fair value and reclassified 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 H).

Preferred Stock and Warrants

Authorized, Issued, and Outstanding Preferred Stock

In 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 Comp

any 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 June 30, 2016, the Company had 10,000,000 shares of authorized and undesignated preferred stock and did not have any preferred stock outstanding.

Series D-1 Redeemable Convertible Preferred Stock

In February 2015, the Company entered int

o 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-1 redeemable convertible preferred stock (“Series D-1 Preferred”) for $1.25 per share, or an aggregate of $4 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, and as of

June 30, 2016, warrants to purchase 15,499,324 shares of Series D Preferred 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. 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 2, 2019, or upon a liquidation event.

On June

2, 2014, pursuant to the terms of the Deerfield Facility Agreement, the Company issued the Deerfield Warrant to purchase 14,423,076 shares of Series D Preferred. 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 2, 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 liability and stated at fair value a

t 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 determined that the 2013 Warrants should be marked to fair value and reclassified 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 H).