Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Schedule of weighted-average valuation assumptions

	Year Ended December 31,
	2014		2015		2016
Expected volatility	102.86	%	106.38	%	98.83	%
Risk-free interest rate	1.98	%	1.55	%	1.47	%
Weighted-average expected life (in years)	6.6		6.4		6.6
Dividend yield	0.00	%	0.00	%	0.00	%

Schedule of stock option activity

The Company’s stock option activity and related information are summarized as follows:

				Weighted-Average
				Remaining
		Weighted-Average		Contractual Term	Aggregate
	Options	Exercise Price		(In Years)	Intrinsic Value
Outstanding at January 1, 2014	5,246,465	$	6.76
Granted during year	1,065,386		10.54
Exercised during year	(399,654)		3.23
Expired during year	(244,121)		9.17
Forfeited during year	(571,402)		10.49
Outstanding at December 31, 2014	5,096,674	$	7.29	6.87	$	6,329,518
Exercisable at December 31, 2014	2,695,278		5.89	5.68		4,986,059
Outstanding at January 1, 2015	5,096,674		7.29
Granted during year	1,126,672		5.23
Exercised during year	(146,046)		2.60
Expired during year	(156,160)		11.03
Forfeited during year	(234,325)		8.05
Outstanding at December 31, 2015	5,686,815	$	6.87	6.52	$	1,432,306
Exercisable at December 31, 2015	3,391,069		6.46	5.37		1,333,875
Outstanding at January 1, 2016	5,686,815		6.87
Granted during year	1,100,997		3.21
Exercised during year	(129,638)		2.01
Expired during year	(28,369)		7.65
Forfeited during year	(182,211)		4.45
Outstanding at December 31, 2016	6,447,594	$	6.41	6.17	$	33,283
Exercisable at December 31, 2016	4,666,628		6.76	5.34		33,283

Schedule of nonvested stock option activity

		Weighted-Average
	Options	Grant Date Value
Nonvested stock options at January 1, 2014	2,977,027	$	6.62
Granted during year	1,065,386		8.62
Vested during year	(1,069,615)		6.61
Forfeited during year	(571,402)		8.36
Nonvested at December 31, 2014	2,401,396	$	7.07
Nonvested stock options at January 1, 2015	2,401,396	$	7.07
Granted during year	1,126,672		4.34
Vested during year	(997,997)		6.48
Forfeited during year	(234,325)		6.37
Nonvested at December 31, 2015	2,295,746	$	6.05
Nonvested stock options at January 1, 2016	2,295,746	$	6.05
Granted during year	1,100,997		2.58
Vested during year	(1,433,566)		5.74
Forfeited during year	(182,211)		3.57
Nonvested at December 31, 2016	1,780,966	$	4.41

Schedule of restricted stock unit activity

		Weighted-Average
	Restricted	Grant Date
	Stock Units	Fair Value
Outstanding at January 1, 2014	—	$	—
Granted during year	196,710		11.11
Vested during year	(1,875)		11.11
Forfeited during year	(33,396)		11.11
Outstanding at December 31, 2014	161,439	$	11.11
Outstanding at January 1, 2015	161,439		11.11
Granted during year	260,976		5.17
Vested during year	(40,333)		11.11
Forfeited during year	(30,668)		8.07
Outstanding at December 31, 2015	351,414		7.03
Outstanding at January 1, 2016	351,414	$	7.03
Granted during year	254,538		3.21
Vested during year	(177,078)		6.71
Forfeited during year	(34,742)		4.13
Outstanding at December 31, 2016	394,132	$	4.96