Cash Equivalents and Short-Term Investments - Short Term Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Amortized cost, due within one year	$ 195,579	$ 113,613
Estimated fair value, due within one year	195,453	113,623
Amortized cost, due between one and four years	39,019	0
Estimated fair value, due between one and four years	38,839	0
Amortized Cost	234,598	113,613
Estimated Fair Value	$ 234,292	$ 113,623