Note Q - Quarterly Results of Operations (unaudited) - Schedule of Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Operating expenses:
Research and development	7,963	4,287	4,988	3,234	4,716	4,328	2,768	2,119	20,472	13,931	11,917
General and administrative	2,873	3,104	4,287	3,736	2,566	2,152	3,188	977	14,000	8,883	4,526
Restructuring Charges		3,010
Total operating expenses	10,836	10,401	9,275	6,970	7,282	6,480	5,956	3,096	37,482	22,814	16,443
Loss from operations	(10,836)	(10,401)	(9,275)	(6,970)	(7,282)	(6,480)	(5,956)	(3,096)	(37,482)	(22,814)	(16,443)
Other income (expense):
Loss on extinguishment of debt				(4,740)					(4,740)		1,900
Interest expense related to amortization of debt issuance costs and discount	(391)	(390)	(393)	(442)	(475)	(479)	(477)	(477)	(1,616)	(1,909)	(1,114)
Interest expense on principal	(1,445)	(1,441)	(1,475)	(1,150)	(698)	(687)	(654)	(632)	(5,511)	(2,671)	(1,605)
Fair value adjustment	2,723	(1,299)	20,763	10,278	(764)	(2,089)	(22,661)	(1,762)	32,465	(27,276)	(7,223)
Interest and other income	9	98	144	102	15	11	5		353	32	8
Total other income (expense)	896	(3,032)	19,039	4,048	(1,922)	(3,244)	(23,787)	(2,871)	20,951	(31,824)	(8,034)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(9,940)	(13,433)	9,764	(2,922)	(9,204)	(9,724)	(29,743)	(5,967)	(16,531)	(54,638)	(24,477)
Income tax benefit (expense)	4	19	4	(12)	1	(20)		(7)	15	(26)	22
Net loss - basic and diluted	$ (9,936)	$ (13,414)	$ 9,768	$ (2,934)	$ (9,203)	$ (9,744)	$ (29,743)	$ (5,974)	$ (16,516)	$ (54,664)	$ (24,455)
Net loss per share:
Basic (in dollars per share)	$ (0.68)	$ (0.92)	$ 0.59	$ (0.20)	$ (0.64)	$ (0.68)	$ (2.45)	$ (2.50)
Diluted (in dollars per share)	$ (0.68)	$ (0.92)	$ (0.58)	$ (0.20)	$ (0.64)	$ (0.68)	$ (2.45)	$ (2.50)