Quarterly Results of Operations (Unaudited) - Schedule of Quarterly Financial Information (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
Quarterly Financial Information Disclosure [Abstract]
Total operating expenses	$ 13,138	$ 17,481	$ 17,935	$ 11,272	$ 10,101	$ 5,626	$ 4,758	$ 5,349	$ 59,826	$ 25,834	$ 11,940
Operating loss	(13,138)	(17,481)	(17,935)	(11,272)	(10,101)	(5,626)	(4,758)	(5,349)	(59,826)	(25,834)	(11,828)
Other income, net	77	7	31	12	18	30			48	1	9
Loss from continuing operations	(13,061)	(17,474)	(17,904)	(11,260)	(10,083)	(5,596)	(4,758)	(5,349)	(59,699)	(25,786)	(13,103)
Loss from discontinued operations					(1,083)	(480)	(349)	(362)		(2,274)	1,715
Net loss and comprehensive loss	$ (13,061)	$ (17,474)	$ (17,904)	$ (11,260)	$ (11,166)	$ (6,076)	$ (5,107)	$ (5,711)	$ (59,699)	$ (28,060)	$ (11,388)
Income (loss) per share, basic and diluted:
Continuing operations	$ (0.82)	$ (5.76)	$ (7.31)	$ (4.60)	$ (4.37)	$ (2.45)	$ (2.11)	$ (2.39)	$ (9.97)	$ (11.36)	$ (5.95)
Discontinued operations					(0.47)	(0.21)	(0.16)	(0.16)		(1.01)	0.78
Net loss per share, basic and diluted	$ (0.82)	$ (5.76)	$ (7.31)	$ (4.60)	$ (4.84)	$ (2.66)	$ (2.27)	$ (2.55)	$ (9.97)	$ (12.37)	$ (5.17)
Weighted-average common shares outstanding, basic and diluted	15,938,941	3,033,967	2,448,747	2,445,351	2,306,476	2,281,001	2,249,666	2,238,471	5,985,985	2,269,124	2,203,278