Stock-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) period shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Jun. 30, 2015 shares
Stock Based Compensation
Shares granted	6,096,000
2015 Plan
Stock Based Compensation
Shares reserved for issuance				3,451,495
Shares reserved for issuance as a proportion of common stock outstanding (as a percent)	4.00%
2015 Plan | Minimum
Stock Based Compensation
Shares reserved for issuance	3,500,000
Employee stock purchase plan
Stock Based Compensation
Shares reserved for issuance	3,772,225
Additional shares reserved for issuance	880,000
Shares reserved for issuance as a proportion of common stock outstanding (as a percent)	1.00%
Price in relation to fair market value of common stock on the date of grant, lower range limit (as a percent)	85.00%
Maximum number of shares a participant may receive during the period (in shares)	5,000
Maximum amount of award or purchase during a calendar year | $	$ 25,000
Maximum offering period, term	27 months
Number of expected offering periods each year | period	2
Offering period, expected term	6 months
Maximum employee contribution of employee's cash compensation (as a percent)	15.00%
Performance-based awards
Stock Based Compensation
Stock-based compensation expense | $	$ 54,200,000	$ 48,200,000
Options to purchase common stock
Stock Based Compensation
Stock-based compensation expense | $	$ 191,808,000	$ 152,384,000	$ 115,219,000
Shares available for issuance	1,102,000	3,263,000
Options outstanding (in shares)	5,501,000	5,300,000
Restricted stock units
Stock Based Compensation
Number of shares vested	2,750
Shares granted	6,096
Non-employee stock options
Stock Based Compensation
Stock-based compensation expense | $	$ 4,462,000	$ 2,445,000	$ 1,533,000
Options outstanding (in shares)	0