Cash, Cash Equivalents, and Marketable Debt Securities - Schedule of Marketable Debt Securities in Continuous Loss Position (Details) $ in Millions	Mar. 31, 2021 USD ($) security	Dec. 31, 2020 USD ($) security
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $	$ 64.6	$ 48.1
Number of Marketable Debt Securities in a Loss Position | security	87	62
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $	$ 60.4	$ 42.9
Number of Marketable Debt Securities in a Loss Position | security	79	56
U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $	$ 0.5
Number of Marketable Debt Securities in a Loss Position | security	1
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $	$ 2.5	$ 1.7
Number of Marketable Debt Securities in a Loss Position | security	5	3
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $	$ 1.2	$ 1.3
Number of Marketable Debt Securities in a Loss Position | security	2	2
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Fair Value of Marketable Debt Securities | $		$ 2.2
Number of Marketable Debt Securities in a Loss Position | security		1