CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,828	$ 9,953	$ 6,501	$ 25,510
Other comprehensive income, net of applicable taxes:
Foreign currency translation adjustment	(3,892)	2,257	(2,452)	3,305
Unrealized loss on short-term investments			0	(30)
Total other comprehensive (loss) income	(3,892)	2,257	(2,452)	3,275
Comprehensive income	$ 936	$ 12,210	$ 4,049	$ 28,785

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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