Stockholders' Equity - Outstanding and Reserved Shares of Common Stock for Future Issuance (Detail) - shares	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Common stock outstanding and reserved shares of common stock for future issuance
Options outstanding (in shares)	454,000	522,000
Total shares of common stock reserved for future issuance (in shares)	44,630,000
2012 Equity Incentive Plan
Common stock outstanding and reserved shares of common stock for future issuance
Total shares of common stock reserved for future issuance (in shares)	26,603,000
2012 Employee Stock Purchase Plan
Common stock outstanding and reserved shares of common stock for future issuance
Total shares of common stock reserved for future issuance (in shares)	9,526,000
Options outstanding
Common stock outstanding and reserved shares of common stock for future issuance
Options outstanding (in shares)	454,000
RSUs
Common stock outstanding and reserved shares of common stock for future issuance
RSUs (in shares)	8,047,000	7,362,000
Performance-based RSUs
Common stock outstanding and reserved shares of common stock for future issuance
Number of shares eligible to vest (percent)	100.00%