Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit
Balance at beginning of period at Dec. 31, 2017	$ 151,557	$ 372	$ 389,786	$ (1,142)	$ (237,459)
Balance at beginning of period (shares) at Dec. 31, 2017		37,109,556
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	4,820		4,820
Restricted stock vested (in shares)		84,262
Restricted stock vested	106	$ 1	105
Repurchase of common stock	(261)			(261)
Repurchase of common stock (shares)		(28,720)
Cumulative effect of accounting change	42				42
Net loss	(18,310)				(18,310)
Balance at end of period at Mar. 31, 2018	137,954	$ 373	394,711	(1,403)	(255,727)
Balance at end of period (shares) at Mar. 31, 2018		37,165,098
Balance at beginning of period at Dec. 31, 2018	$ 115,143	$ 373	407,199	(1,417)	(291,012)
Balance at beginning of period (shares) at Dec. 31, 2018	37,251,220	37,251,220
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	$ 1,944		1,944
Restricted stock vested (in shares)	44,329	44,329
Restricted stock vested	$ 0
Repurchase of common stock	(32)			(32)
Repurchase of common stock (shares)		(19,447)
Net loss	(10,036)				(10,036)
Balance at end of period at Mar. 31, 2019	$ 107,019	$ 373	$ 409,143	$ (1,449)	$ (301,048)
Balance at end of period (shares) at Mar. 31, 2019	37,276,102	37,276,102