CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	(Accumulated Deficit) Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Impact to Retained Earnings from adoption | ASU 2014-09	$ 5,730				$ 5,730
Balance	509,260	$ 355	$ (6,030)	$ 630,341	(114,672)	$ (734)
Balance at Dec. 31, 2017	503,530	355	(6,030)	630,341	(120,402)	(734)
Net income	14,551				14,551
Foreign currency translation	629					629
Stock-based compensation expense	1,467			1,467
Stock options exercised	566			566
Balance at Mar. 31, 2018	526,473	355	(6,030)	632,374	(100,121)	(105)
Impact to Retained Earnings from adoption | ASU 2016-02	9,153				9,153
Balance	598,856	356	(6,030)	639,381	(32,334)	(2,517)
Balance at Dec. 31, 2018	589,703	356	(6,030)	639,381	(41,487)	(2,517)
Net income	19,198				19,198
Foreign currency translation	(274)					(274)
Stock-based compensation expense	3,183			3,183
Stock options exercised	934	1		933
Balance at Mar. 31, 2019	$ 621,897	$ 357	$ (6,030)	$ 643,497	$ (13,136)	$ (2,791)