Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Schedule of weighted-average valuation assumptions

	Three Months Ended September 30,			Nine Months Ended September 30,
	2016		2017	2016		2017
Expected volatility	95.9	%	—	99.0	%	92.7	%
Risk-free interest rate	1.27	%	—	1.47	%	2.15	%
Weighted-average expected life (in years)	6.3		—	6.6		6.9
Dividend yield	0.00	%	—	0.00	%	0.00	%

Schedule of stock option activity

				Weighted-Average
				Remaining
		Weighted-Average		Contractual Term	Aggregate
	Options	Exercise Price		(In Years)	Intrinsic Value(1)
Outstanding at January 1, 2017	6,447,594	$	6.41
Granted during period	653,842		2.17
Exercised during period	(7,757)		2.10
Expired during period	(163,836)		8.82
Forfeited during period	(68,875)		5.59
Outstanding at March 31, 2017	6,860,968	$	5.96	6.27	$	282,786
Exercisable at March 31, 2017	5,085,833	$	6.72	5.33	$	29,895
Outstanding at April 1, 2017	6,860,968		5.96
Granted during period	198,350		2.27
Exercised during period	(44,501)		2.10
Expired during period	(123,874)		8.41
Forfeited during period	(225,402)		4.15
Outstanding at June 30, 2017	6,665,541	$	5.89	6.09	$	—
Exercisable at June 30, 2017	5,083,084	$	6.63	5.22	$	—
Outstanding at July 1, 2017	6,665,541		5.89
Granted during period	—		—
Exercised during period	—		—
Expired during period	(336,625)		7.08
Forfeited during period	(63,583)		4.71
Outstanding at September 30, 2017	6,265,333	$	5.84	5.83	$	—
Exercisable at September 30, 2017	4,770,246		6.59	4.94		—

Schedule of restricted stock unit activity

	Restricted	Weighted-Average
	Stock	Grant
	Units	Date Fair Value
Outstanding at January 1, 2017	394,132	$	4.96
Granted during period	367,985		2.17
Vested during period	(128,225)		5.77
Forfeited during period	(16,980)		3.50
Outstanding at March 31, 2017	616,912	$	3.17
Outstanding at April 1, 2017	616,912	$	3.17
Granted during period	26,400		2.27
Vested during period	(23,950)		3.25
Forfeited during period	(94,569)		3.06
Outstanding at June 30, 2017	524,793	$	3.14
Outstanding at July 1, 2017	524,793	$	3.14
Granted during period	—		—
Vested during period	(5,937)		4.85
Forfeited during period	(40,769)		3.20
Outstanding at September 30, 2017	478,087	$	3.11