Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Stockholders Equity, Beginning Balance at Dec. 31, 2017	$ 94,726	$ 52	$ 718,751	$ (624,077)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2017		52,395,223
Issuance of common stock for exercise of stock options	178		178
Issuance of common stock for exercise of stock options, Shares		118,942
Stock-based compensation	5,102		5,102
Issuance of stock, value	45,996	$ 22	45,974
Issuance of stock, shares		21,850,000
Issuance of common stock warrant	116		116
Net loss	(39,052)			(39,052)
Stockholders Equity, Ending Balance at Sep. 30, 2018	$ 107,066	$ 74	$ 770,121	$ (663,129)
Stockholders Equity, Ending Balance, Shares at Sep. 30, 2018		74,364,165