CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings (Accumulated Deficit) [Member]
Balance at Dec. 31, 2017	$ 333,154	$ 32	$ 386,196	$ (1,205)	$ (51,869)
Balance, Shares at Dec. 31, 2017		31,604
Issuance of shares through share-based compensation plans, net	122		122
Issuance of shares through share-based compensation plans, net, Shares		169
Net income	15,130				15,130
Share-based compensation	1,507		1,507
Share-based compensation plan withholdings	(839)		(839)
Share-based compensation plan withholdings, Shares		(31)
Currency translation	632			632
Unrealized gain on investments	23			23
Balance at Mar. 31, 2018	349,729	$ 32	386,986	(550)	(36,739)
Balance, shares at Mar. 31, 2018		31,742
Balance at Dec. 31, 2018	361,888	$ 31	369,893	(1,263)	(6,773)
Balance, Shares at Dec. 31, 2018		30,906
Issuance of shares through share-based compensation plans, net, Shares		103
Repurchase of common stock	(744)		(744)
Repurchase of common stock, Shares		(37)
Net income	7,576				7,576
Share-based compensation	2,163		2,163
Share-based compensation plan withholdings	(598)		(598)
Share-based compensation plan withholdings, Shares		(27)
Currency translation	(518)			(518)
Unrealized gain on investments	95			95
Balance at Mar. 31, 2019	$ 369,862	$ 31	$ 370,714	$ (1,686)	$ 803
Balance, shares at Mar. 31, 2019		30,945