Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020		Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 390,260	$ 173,415	[1]	$ 67,326
Restricted cash	1,988	203	[1]	203
Cash, cash equivalents and restricted cash	$ 392,248	$ 173,618		$ 67,529	$ 58,140

[1] The Condensed Consolidated Balance Sheet as of December 31, 2020 has been derived from the audited financial statements as of that date.