Condensed Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 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	133		133
Issuance of common stock for exercise of stock options, Shares		88,958
Stock-based compensation	3,281		3,281
Issuance of stock, value	45,996	$ 22	45,974
Issuance of stock, shares		21,850,000
Net loss	(23,485)			(23,485)
Stockholders Equity, Ending Balance at Jun. 30, 2018	$ 120,651	$ 74	$ 768,139	$ (647,562)
Stockholders Equity, Ending Balance, Shares at Jun. 30, 2018		74,334,181