Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies
Cash and cash equivalents	$ 139,520	$ 24,930	$ 51,885
Restricted cash	121		235
Total	$ 139,641	$ 25,051	$ 52,120	$ 10,376