Net Loss Per Share - Schedule of Anti-dilutive Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total shares excluded from calculation	5,314	3,686	5,119	5,128
Stock Options and ESPP [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total shares excluded from calculation	3,634	3,686	3,699	5,128
Convertible Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total shares excluded from calculation	1,680		1,420