CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 21,383	$ 14,133	$ 42,133	$ 26,355
Other comprehensive income (loss), net of tax:
Foreign currency translation			1
Unrealized gains (losses) on marketable securities	102	25	228	(59)
Other comprehensive income (loss)	102	25	229	(59)
Comprehensive income	$ 21,485	$ 14,158	$ 42,362	$ 26,296