CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net loss	$ (11,244)	$ (21,335)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	21	22
Amortization of warrant issuance costs	0	30
Stock-based compensation	2,780	3,979
Changes in assets and liabilities:
Prepaid expenses and other assets	184	238
Accounts payable and accrued liabilities	(1,004)	549
Accrued payroll and related expenses	(1,270)	(1,290)
Other current liabilities	140	0
Royalty payable	0	884
Related-party payable	0	83
Income tax liability	(2)	0
Deferred revenue	(1,125)	1,375
Net cash used in operating activities	(11,520)	(15,465)
Cash flows from investing activities:
Purchase of property and equipment	0	(14)
Purchase of investments	(756)	(7,888)
Proceeds from sale or maturity of investments	7,338	8,615
Net cash provided by investing activities	6,582	713
Cash flows from financing activities:
Proceeds from exercise of options	0	20
Proceeds from sale of common stock	0	14,626
Payments of taxes on cashless exercise of restricted stock units	(42)	(93)
Net cash (used in) provided by financing activities	(42)	14,553
Net decrease in cash and cash equivalents	(4,980)	(199)
Cash and cash equivalents, beginning of period	6,627	8,726
Cash and cash equivalents, end of period	1,647	8,527
Cash paid for income taxes	$ 0	$ 126