Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Collaboration revenue	$ 406,000	$ 490,000	$ 2,243,000
License revenue	29,575,000	500,000	0
Total revenue	29,981,000	990,000	2,243,000
Operating expenses:
Research and development	13,479,000	26,336,000	26,703,000
General and administrative	14,736,000	9,850,000	8,471,000
(Gain) loss from change in fair value of contingent consideration	(1,100,000)	0	0
Total operating expenses	27,115,000	36,186,000	35,174,000
Income (loss) from operations	2,866,000	(35,196,000)	(32,931,000)
Other income (expense):
Other income (expense), net	(723,000)	3,139,000	(849,000)
Interest expense	(247,000)	(1,395,000)	(376,000)
Total other income (expense), net	(970,000)	1,744,000	(1,225,000)
Net income (loss) before income taxes	1,896,000	(33,452,000)	(34,156,000)
Provision for income taxes	5,000	0	0
Net income (loss) and comprehensive income (loss)	1,891,000	(33,452,000)	(34,156,000)
Cumulative preferred stock dividends and accretion of preferred stock discount	0	0	(519,000)
Net income (loss) applicable to common stockholders	$ 1,891,000	$ (33,452,000)	$ (34,675,000)
Net income (loss) per share applicable to common stockholders—basic	$ 0.09	$ (1.76)	$ (2.37)
Weighted-average number of common shares used in net income (loss) per share applicable to common stockholders—basic	21,083	18,993	14,644
Net income (loss) per share applicable to common stockholders-diluted	$ 0.09	$ (1.76)	$ (2.37)
Weighted Average Number of Shares Outstanding, Diluted	21,733	18,993	14,644