The Company and Significant Accounting Policies - Summary of Components of AOCI (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	$ 248,237	$ 288,172	$ 323,730	$ 288,172	$ 332,732
Other comprehensive income (loss)	1,200	(500)
Income tax (expense) benefit	(200)	100
Total other comprehensive income (loss)	1,001	(400)	205	612	998
Balance, Ending	250,260	248,237	302,921	250,260	302,921
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	(700)	(500)		(500)
Other comprehensive income (loss)	500	(200)
Total other comprehensive income (loss)	500	(200)
Balance, Ending	(200)	(700)		(200)
Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	200	400		400
Other comprehensive income (loss)	700	(300)
Income tax (expense) benefit	(200)	100
Total other comprehensive income (loss)	500	(200)
Balance, Ending	700	200		700
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	(520)	(131)	(619)	(131)	(1,412)
Balance, Ending	$ 481	$ (520)	$ (414)	$ 481	$ (414)