Stock Plans and Stock-Based Compensation - Restricted Stock Units - Additional Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 33,489,000	$ 25,825,000	$ 9,299,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, number of stock unit grants in period	420,149
Stock-based compensation expense	$ 16,300,000	$ 5,400,000	$ 1,100,000
Number of stock units vested	275,023
Weighted-average grant date fair values of units granted	$ 80.16	$ 52.11	$ 26.19
Fair values of stock units	$ 11,900,000	$ 3,100,000	$ 0
Unrecognized compensation expense	$ 34,700,000
Weighted-average amortization period	2 years 6 months

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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