Note 10 - Convertible Preferred Stock Warrant Liability

12 Months Ended

Dec. 31, 2017

Notes to Financial Statements

Convertible Preferred Stock Warrant [Text Block]

( 10 ) Convertible Preferred Stock Warrant Liability

The Company has historically issued warrants to purchase shares of the Company

’s preferred stock in connection with certain preferred stock offerings and note financings.

Upon the completion of the Merger

in

October 2016,

the Company exchanged

20%

and

10%

of outstanding Series D and Series F convertible preferred stock warrants for

6,788

and

4,019

shares of the Company’s common stock, respectively, and cancelled the remaining convertible preferred stock warrants pursuant to the Merger Agreement. Upon the completion of the Merger, the valuation of the convertible preferred stock warrant liability was determined based on the settlement value of the common stock exchanged for the warrants, amounting to

$25,000,

and the Company reclassified the balance of the convertible preferred stock warrant liability to additional paid-in capital.