CONSOLIDATED STATEMENTS OF STOCKHOLDERS' (DEFICIT) EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock
Beginning balance at Dec. 31, 2017	$ 32,172	$ 19	$ 123,838	$ (82,147)	$ (9,538)
Increase (Decrease) in Stockholders' Equity
Net loss	(14,204)			(14,204)
Stock-based compensation expense	799		1,143		(344)
Ending balance at Mar. 31, 2018	20,480	19	124,981	(94,638)	(9,882)
Beginning balance at Dec. 31, 2017	32,172	19	123,838	(82,147)	(9,538)
Increase (Decrease) in Stockholders' Equity
Net loss	(14,204)
Ending balance at Dec. 31, 2018	(18,578)	19	126,412	(135,160)	(9,849)
Increase (Decrease) in Stockholders' Equity
Net loss	(2,586)			(2,586)
Stock-based compensation expense	535		911		(376)
Payment of withholding taxes for net settlement of stock-based awards	(346)		(346)
Ending balance at Mar. 31, 2019	$ (20,975)	$ 19	$ 126,977	$ (137,746)	$ (10,225)