The Company and Significant Accounting Policies - Summary of Components of AOCI (Detail) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	$ 286,962	$ 280,683	$ 275,980	$ 250,260	$ 275,980	$ 288,172
Other comprehensive income (loss)	200	(300)	300
Total other comprehensive income (loss)	225	(300)	300	(446)	253	166
Balance, Ending	253,270	286,962	280,683	257,540	253,270	257,540
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	(1,300)	(1,000)	(1,400)		(1,400)
Other comprehensive income (loss)	200	(300)	400
Total other comprehensive income (loss)	200	(300)	400
Balance, Ending	(1,100)	(1,300)	(1,000)		(1,100)
Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	300	300	400		400
Other comprehensive income (loss)			(100)
Total other comprehensive income (loss)			(100)
Balance, Ending	300	300	300		300
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, Beginning	(1,028)	(718)	(1,056)	481	(1,056)	(131)
Balance, Ending	$ (803)	$ (1,028)	$ (718)	$ 35	$ (803)	$ 35