Fair Value Measurements and Investments in Marketable Securities - Schedule of Investments in Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Investments in marketable securities:
Amortized Cost	$ 24,006	$ 38,344
Investment, Type [Extensible Enumeration]	Cash equivalents	Cash equivalents
Amortized Cost, Short-term marketable securities	$ 50,980	$ 73,673
Gross Unrealized Gain, Short-term marketable securities	4	65
Gross Unrealized Loss, Short-term marketable securities	(10)	(3)
Fair Value, Short-term marketable securities	50,974	73,735
Amortized Cost	74,425	111,176
Gross Unrealized Gain	4	65
Gross Unrealized Loss	(10)	(3)
Fair Value	74,419	111,238
Cash equivalents
Investments in marketable securities:
Amortized Cost	23,445	37,503
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	23,445	37,503
Money market fund \| Cash equivalents
Investments in marketable securities:
Amortized Cost	23,445	29,066
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	23,445	29,066
Corporate debt securities
Investments in marketable securities:
Amortized Cost, Short-term marketable securities	14,167	20,971
Gross Unrealized Gain, Short-term marketable securities	4	20
Gross Unrealized Loss, Short-term marketable securities	(1)	(3)
Fair Value, Short-term marketable securities	14,170	20,988
U.S. treasury securities
Investments in marketable securities:
Amortized Cost, Short-term marketable securities	33,214	48,077
Gross Unrealized Gain, Short-term marketable securities	0	40
Gross Unrealized Loss, Short-term marketable securities	(7)	0
Fair Value, Short-term marketable securities	33,207	48,117
U.S. treasury securities \| Cash equivalents
Investments in marketable securities:
Amortized Cost		8,437
Gross Unrealized Gain		0
Gross Unrealized Loss		0
Fair Value		8,437
Commercial paper
Investments in marketable securities:
Amortized Cost, Short-term marketable securities	3,599	4,625
Gross Unrealized Gain, Short-term marketable securities	0	5
Gross Unrealized Loss, Short-term marketable securities	(2)	0
Fair Value, Short-term marketable securities	$ 3,597	$ 4,630

ASSEMBLY BIOSCIENCES, INC. 10-Q