CONDENSED STATEMENT OF STOCKHOLDERS' EQUITY - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Beginning balance at Dec. 31, 2017	$ 196	$ 711,993	$ (604,494)	$ 107,695
Beginning balance, shares at Dec. 31, 2017	195,625			195,625,000
Issuance of common stock under stock purchase plan		81		$ 81
Issuance of common stock under stock purchase plan, shares	53
Issuance of common stock upon exercise of common stock warrants	$ 20	9,571		9,591
Issuance of common stock upon exercise of common stock warrants, shares	20,406
Issuance of common stock for services rendered		23		23
Issuance of common stock for services rendered, shares	11
Stock-based compensation		1,589		1,589
Net loss			(20,095)	(20,095)
Ending balance at Mar. 31, 2018	$ 216	$ 723,257	$ (624,589)	$ 98,884
Ending balance, shares at Mar. 31, 2018	216,095			216,095,000