Stock Plans and Stock-Based Compensation - Stock Options - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 13,351	$ 8,301	$ 34,939	$ 24,094
Intrinsic value of options exercised			26,100	44,500
Intrinsic value of all outstanding options	42,800	28,200	42,800	28,200
Total unrecognized compensation cost	3,700		3,700
Proceeds from stock option exercises			$ 6,764	$ 15,822
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period			4 years
Stock options expiration period			10 years
Stock options granted			0	0
Stock-based compensation expense	$ 900	$ 1,300	$ 2,800	$ 4,700
Weighted-average amortization period			1 year 2 months 12 days

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

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