Cash, Cash Equivalents and Investment Debt Securities (Cash, Cash Equivalents and Investment Debt Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Cash and cash equivalents:
Cash and Cash Equivalents, Amortized Cost	$ 113,199	$ 84,709
Cash and Cash Equivalents, Gross Unrealized Losses	(4)
Cash and cash equivalents, Fair Value	113,195	84,709
Investment Debt Securities Abstract
Total investments, Amortized Cost	380,128	335,260
Total cash and cash equivalents and investment debt securities, Amortized Cost	493,327	419,969
Allowance for Credit Losses	0
Total investments, Gross Unrealized Gains	1	16
Total cash and cash equivalents and investment debt securities, Gross Unrealized Gains	1	16
Total investments, Gross Unrealized Losses	(2,473)	(296)
Total cash and cash equivalents and investment debt securities, Gross Unrealized Losses	(2,477)	(296)
Total investments, Fair Value	377,656	334,980
Total cash and cash equivalents and investment debt securities, Fair Value	490,851	419,689
Commercial paper
Investment Debt Securities Abstract
Total investments, Amortized Cost	108,091	84,513
Allowance for Credit Losses	0
Total investments, Gross Unrealized Gains	0
Total investments, Gross Unrealized Losses	(254)	(49)
Total investments, Fair Value	107,837	84,464
Corporate debt securities
Investment Debt Securities Abstract
Total investments, Amortized Cost	245,321	232,721
Allowance for Credit Losses	0
Total investments, Gross Unrealized Gains	0	16
Total investments, Gross Unrealized Losses	(2,018)	(245)
Total investments, Fair Value	243,303	232,492
Municipal bonds
Investment Debt Securities Abstract
Total investments, Amortized Cost		5,028
Total investments, Gross Unrealized Losses		(1)
Total investments, Fair Value		5,027
U.S. government agency bonds
Investment Debt Securities Abstract
Total investments, Amortized Cost	11,751
Total investments, Gross Unrealized Gains	1
Total investments, Gross Unrealized Losses	(117)
Total investments, Fair Value	11,635
U.S Treasury securities
Investment Debt Securities Abstract
Total investments, Amortized Cost	14,965	12,998
Total investments, Gross Unrealized Gains	0
Total investments, Gross Unrealized Losses	(84)	(1)
Total investments, Fair Value	14,881	12,997
Cash and money market funds
Cash and cash equivalents:
Cash and Cash Equivalents, Amortized Cost	95,225	76,709
Cash and cash equivalents, Fair Value	95,225	76,709
Commercial paper
Cash and cash equivalents:
Cash and Cash Equivalents, Amortized Cost	13,977	8,000
Cash and Cash Equivalents, Gross Unrealized Losses	(4)
Cash and cash equivalents, Fair Value	13,973	$ 8,000
Corporate debt securities
Cash and cash equivalents:
Cash and Cash Equivalents, Amortized Cost	3,997
Cash and cash equivalents, Fair Value	$ 3,997