Marketable Securities - Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Short-term AFS securities
Amortized cost, short-term AFS securities	$ 173,610	$ 164,612
Gross unrealized gains, short-term AFS securities	32	61
Gross unrealized losses, short-term AFS securities	(1,404)	(2,579)
Fair value, short-term AFS securities	172,238	162,094
Long-term AFS securities
Amortized cost, long-term AFS securities	307,213	255,796
Gross unrealized gains, long-term AFS securities	531	1,909
Gross unrealized losses, long-term AFS securities	(540)	(72)
Fair value, long-term AFS securities	307,204	257,633
U.S. Treasury securities
Short-term AFS securities
Amortized cost, short-term AFS securities	87,303	48,721
Gross unrealized gains, short-term AFS securities	25	55
Gross unrealized losses, short-term AFS securities	(512)	(667)
Fair value, short-term AFS securities	86,816	48,109
Long-term AFS securities
Amortized cost, long-term AFS securities	146,981	148,878
Gross unrealized gains, long-term AFS securities	179	1,023
Gross unrealized losses, long-term AFS securities	(328)	(42)
Fair value, long-term AFS securities	146,832	149,859
Corporate debt securities
Short-term AFS securities
Amortized cost, short-term AFS securities	83,352	109,891
Gross unrealized gains, short-term AFS securities	7	6
Gross unrealized losses, short-term AFS securities	(848)	(1,828)
Fair value, short-term AFS securities	82,511	108,069
Long-term AFS securities
Amortized cost, long-term AFS securities	158,301	103,061
Gross unrealized gains, long-term AFS securities	352	886
Gross unrealized losses, long-term AFS securities	(190)	(5)
Fair value, long-term AFS securities	158,463	103,942
U.S. governmental agency securities
Short-term AFS securities
Amortized cost, short-term AFS securities	2,955	6,000
Gross unrealized gains, short-term AFS securities	0	0
Gross unrealized losses, short-term AFS securities	(44)	(84)
Fair value, short-term AFS securities	2,911	5,916
Long-term AFS securities
Amortized cost, long-term AFS securities	1,931	3,857
Gross unrealized gains, long-term AFS securities	0	0
Gross unrealized losses, long-term AFS securities	(22)	(25)
Fair value, long-term AFS securities	$ 1,909	$ 3,832