Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
BALANCE - value at Dec. 31, 2015	$ 252,173	$ 6	$ (1,433)	$ 283,247	$ (27,664)	$ (1,983)
BALANCE - shares at Dec. 31, 2015		60,709	(278)
Share-based compensation, value	2,455			2,455
Share-based compensation, shares		148
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(171)			(171)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		74
Exercise of stock options and purchases from employee stock purchase plan, value	905			905
Exercise of stock options and purchases from employee stock purchase plan, shares		309
Excess income tax benefit from share-based compensation	(133)			(133)
Net loss	(8,177)				(8,177)
Other comprehensive income (loss)—net of tax	838					838
BALANCE - value at Dec. 31, 2016	247,890	$ 6	$ (1,433)	286,303	(35,841)	(1,145)
BALANCE - shares at Dec. 31, 2016		61,240	(278)
Share-based compensation, value	2,963			2,963
Share-based compensation, shares		248
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(328)			(328)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		147
Exercise of stock options and purchases from employee stock purchase plan, value	883			883
Exercise of stock options and purchases from employee stock purchase plan, shares		262
Net loss	(31,260)				(31,260)
Other comprehensive income (loss)—net of tax	1,148					1,148
BALANCE - value at Dec. 31, 2017	221,296	$ 6	$ (1,433)	289,821	(67,101)	3
BALANCE - shares at Dec. 31, 2017		61,897	(278)
Cumulative effect of recent accounting pronouncements	(1,577)				(1,577)
Share-based compensation, value	5,425			5,425
Share-based compensation, shares		132
Vesting of restricted stock units, including impact of shares withheld for taxes, value	(1,205)			(1,205)
Vesting of restricted stock units, including impact of shares withheld for taxes, shares		520
Exercise of stock options and purchases from employee stock purchase plan, value	$ 1,094			1,094
Exercise of stock options and purchases from employee stock purchase plan, shares	62	281
Net loss	$ (6,293)				(6,293)
Other comprehensive income (loss)—net of tax	(3,812)					(3,812)
BALANCE - value at Dec. 31, 2018	$ 214,928	$ 6	$ (1,433)	$ 295,135	$ (74,971)	$ (3,809)
BALANCE - shares at Dec. 31, 2018		62,830	(278)