CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit
Balance, beginning of period (in shares) at Dec. 31, 2016		110,212,547		349,760
Balance, beginning of period at Dec. 31, 2016	$ 48,067	$ 110	$ 161,481	$ (2,216)	$ (111,308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	21,195		21,195
Exercise of stock options (in shares)		1,097,933		(1,396,803)
Exercise of stock options	11,987	$ 1	(3,433)	$ 15,419
Issuance of restricted stock (in shares)		1,393,446		(1,954,068)
Issuance of restricted stock	0	$ 2	(17,840)	$ 17,838
Restricted stock cancellation/forfeited (in shares)				320,117
Restricted stock cancellation / forfeited	0		3,205	$ (3,205)
Shares issued for services performed (in shares)				(17,539)
Shares issued for services performed	$ 166		41	$ 125
Shares repurchased (in shares)	5,635,077			5,635,077
Shares repurchased	$ (68,263)			$ (68,263)
Shares repurchased for tax withholding on vesting of restricted stock units (in shares)				419,865
Shares repurchased for tax withholding on vesting of restricted stock units	(4,082)			$ (4,082)
Net (loss) income	64,727				64,727
Balance, end of period (in shares) at Dec. 31, 2017		112,703,926		3,356,409
Balance, end of period at Dec. 31, 2017	73,797	$ 113	164,649	$ (44,384)	(46,581)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	14,768		14,768
Exercise of stock options (in shares)				(786,708)
Exercise of stock options	3,555		(8,210)	$ 11,765
Issuance of restricted stock (in shares)				(1,947,475)
Issuance of restricted stock	0		(25,657)	$ 25,657
Restricted stock cancellation/forfeited (in shares)				1,861,314
Restricted stock cancellation / forfeited	0		19,194	$ (19,194)
Shares issued for services performed	$ 0
Shares repurchased (in shares)	507,600			507,600
Shares repurchased	$ (7,572)			$ (7,572)
Shares repurchased for tax withholding on vesting of restricted stock units (in shares)				614,123
Shares repurchased for tax withholding on vesting of restricted stock units	(4,914)			$ (4,914)
Net (loss) income	(29,979)
Balance, end of period (in shares) at Dec. 31, 2018		112,703,926		3,605,263
Balance, end of period at Dec. 31, 2018	49,655	$ 113	164,744	$ (38,642)	(76,560)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation expense	$ 11,689		11,689
Exercise of stock options (in shares)	150,000			(150,000)
Exercise of stock options	$ 108		(1,343)	$ 1,451
Issuance of restricted stock (in shares)				(3,084,875)
Issuance of restricted stock	0		(37,798)	$ 37,798
Restricted stock cancellation/forfeited (in shares)				1,084,971
Restricted stock cancellation / forfeited	0		9,939	$ (9,939)
Shares issued for services performed	0
Shares repurchased for tax withholding on vesting of restricted stock units (in shares)				429,918
Shares repurchased for tax withholding on vesting of restricted stock units	(1,474)			$ (1,474)
Net (loss) income	(25,580)				(25,580)
Balance, end of period (in shares) at Dec. 31, 2019		112,703,926		1,885,277
Balance, end of period at Dec. 31, 2019	$ 34,398	$ 113	$ 147,231	$ (10,806)	$ (102,140)