Segment Information - Schedule of Segment Expenses and Segment Operating Loss (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Total research and development expense		$ 29,584	$ 57,575
Total general and administrative		9,457	12,231
Stock based compensation		6,951	12,586
Net loss		(34,272)	(63,169)
Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1]	26,144	51,594
Total general and administrative	[2]	5,946	5,626
Stock based compensation		6,951	12,586
Other segment items	[3]	(4,769)	(6,637)
Net loss		(34,272)	(63,169)
COVID-19 external costs | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1],[4]	1,234	39,051
HCV external costs | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1],[4]	17,584	5,953
Early stage discovery external costs | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1],[4]	331	201
Compensation and related expenses | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1]	6,037	5,675
Total general and administrative	[2]	2,678	2,541
Consulting and professional fees | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1]	519	296
Total general and administrative	[2]	2,939	2,585
Other research and development expenses | Operating Segment
Segment Reporting Information [Line Items]
Total research and development expense	[1]	439	418
Other general and administrative | Operating Segment
Segment Reporting Information [Line Items]
Total general and administrative	[2]	$ 329	$ 500

[1] (1)Research and development expense for the three months ended March 31, 2025 and 2024 excludes stock based compensation of $3,440 and $5,981, respectively.

[2] (3)General and administrative expense for the three months ended March 31, 2025 and 2024 excludes stock based compensation of $3,511 and $6,605, respectively.

[3] (4)Other segment items include interest income and other, net and income tax expense.

[4] (2)External costs consist primarily of preclinical, clinical and manufacturing related activities.