Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance, shares at Dec. 31, 2016		32,135
Beginning balance at Dec. 31, 2016	$ 100,822	$ 3,210	$ 296,316	$ (204,104)	$ 5,400
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, shares		78
Common stock issued under employee benefit plans	326	$ 7	319
Share-based compensation, shares		536
Share-based compensation	5,945	$ 54	5,891
Cancellation of restricted shares, shares		(10)
Cancellation of restricted shares	(13)	$ 0	(13)
Issuance of common stock for bonuses and director fees, shares		314
Issuance of common stock for bonuses and director fees	1,803	$ 31	1,772
Issuance of common stock for acquisition, shares		4,147
Issuance of common stock for acquisiton	25,294	$ 415	24,879
Equity component of convertible senior notes issued	8,377		8,377
Net loss	(43,129)			(43,129)
Foreign currency translation adjustments	5,131				5,131
Pension adjustment, net of tax provision (benefit)	1,545				1,545
Ending balance, shares at Dec. 31, 2017		37,200
Ending balance at Dec. 31, 2017	106,101	$ 3,717	337,541	(247,233)	12,076
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee benefit plans, shares		160
Common stock issued under employee benefit plans	444	$ 16	428
Share-based compensation, shares		496
Share-based compensation	6,357	$ 49	6,308
Proceeds from issuance of common stock, net, shares		7,590
Proceeds from issuance of common stock, net	22,950	$ 759	22,191
Issuance of common stock for bonuses and director fees, shares		550
Issuance of common stock for bonuses and director fees	3,381	$ 56	3,325
Issuance of common stock for acquisiton	0
Net loss	(36,548)			(36,548)
Foreign currency translation adjustments	(1,694)				(1,694)
Pension adjustment, net of tax provision (benefit)	(558)				(558)
Other comprehensive income recognized in connection with divestiture	(10,120)				(10,120)
Ending balance, shares at Dec. 31, 2018		45,996
Ending balance at Dec. 31, 2018	$ 90,591	$ 4,597	$ 369,793	$ (283,503)	$ (296)