Condensed Consolidated Statement of Changes in Redeemable Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock Series A Redeemable Convertible Preferred Stock	Preferred Stock Series B Redeemable Convertible Preferred Stock	Common Stock	Treasury Stock, at cost	Additional Paid-in Capital	Accumulated Deficit
Balance at beginning of period (in shares) at Dec. 31, 2019		978,849	1,989,616	1,177,933
Balance at beginning of period at Dec. 31, 2019	$ (59,463)	$ 21,904	$ 41,631	$ 12	$ 0	$ 202	$ (59,677)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of preferred stock to current redemption value (pre-merger)	(651)	$ 216	$ 435				(651)
Issuance of common stock to former stockholders of NewLink upon merger (in shares)				4,146,405
Issuance of common stock to former stockholders of NewLink upon merger	116,949			$ 41		116,908
Conversion of preferred stock into common stock upon merger (in shares)		978,849	1,989,616	2,968,465
Conversion of preferred stock into common stock upon merger	64,186	$ (22,120)	$ (42,066)	$ 30		64,156
Share-based compensation	177					177
Net income (loss)	340						340
Balance at end of period (in shares) at Mar. 31, 2020		0	0	8,292,803
Balance at end of period at Mar. 31, 2020	121,538	$ 0	$ 0	$ 83	0	181,443	(59,988)
Balance at beginning of period (in shares) at Dec. 31, 2019		978,849	1,989,616	1,177,933
Balance at beginning of period at Dec. 31, 2019	(59,463)	$ 21,904	$ 41,631	$ 12	0	202	(59,677)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(3,248)
Balance at end of period (in shares) at Sep. 30, 2020		0	0	8,293,312
Balance at end of period at Sep. 30, 2020	118,535	$ 0	$ 0	$ 83	0	182,028	(63,576)
Balance at beginning of period (in shares) at Mar. 31, 2020		0	0	8,292,803
Balance at beginning of period at Mar. 31, 2020	121,538	$ 0	$ 0	$ 83	0	181,443	(59,988)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	274					274
Sales of shares under stock purchase plan (in shares)				509
Sales of shares under stock purchase plan	6					6
Net income (loss)	(5,353)						(5,353)
Balance at end of period (in shares) at Jun. 30, 2020		0	0	8,293,312
Balance at end of period at Jun. 30, 2020	116,465	$ 0	$ 0	$ 83	0	181,723	(65,341)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	305					305
Net income (loss)	1,765						1,765
Balance at end of period (in shares) at Sep. 30, 2020		0	0	8,293,312
Balance at end of period at Sep. 30, 2020	118,535	$ 0	$ 0	$ 83	0	182,028	(63,576)
Balance at beginning of period (in shares) at Dec. 31, 2020		0	0	8,305,269
Balance at beginning of period at Dec. 31, 2020	116,572	$ 0	$ 0	$ 83	0	182,480	(65,991)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	1,049					1,049
Exercise of stock options (in shares)				20,362
Exercise of stock options	26					26
Stock issued upon vesting of restricted stock units (in shares)				9,939
Shares surrendered for tax withholding on vested awards (in shares)				(3,377)
Shares surrendered for tax withholding on vested awards	(44)				(44)
Net income (loss)	(8,631)						(8,631)
Balance at end of period (in shares) at Mar. 31, 2021		0	0	8,332,193
Balance at end of period at Mar. 31, 2021	108,972	$ 0	$ 0	$ 83	(44)	183,555	(74,622)
Balance at beginning of period (in shares) at Dec. 31, 2020		0	0	8,305,269
Balance at beginning of period at Dec. 31, 2020	116,572	$ 0	$ 0	$ 83	0	182,480	(65,991)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(24,789)
Balance at end of period (in shares) at Sep. 30, 2021		0	0	8,357,391
Balance at end of period at Sep. 30, 2021	94,124	$ 0	$ 0	$ 83	(114)	184,935	(90,780)
Balance at beginning of period (in shares) at Mar. 31, 2021		0	0	8,332,193
Balance at beginning of period at Mar. 31, 2021	108,972	$ 0	$ 0	$ 83	(44)	183,555	(74,622)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	846					846
Exercise of stock options (in shares)				6,560
Exercise of stock options	38					38
Sales of shares under stock purchase plan (in shares)				695
Sales of shares under stock purchase plan	6					6
Stock issued upon vesting of restricted stock units (in shares)				23,994
Shares surrendered for tax withholding on vested awards (in shares)				(6,051)
Shares surrendered for tax withholding on vested awards	(70)				(70)
Net income (loss)	(8,670)						(8,670)
Balance at end of period (in shares) at Jun. 30, 2021		0	0	8,357,391
Balance at end of period at Jun. 30, 2021	101,122	$ 0	$ 0	$ 83	(114)	184,445	(83,292)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	490					490
Net income (loss)	(7,488)						(7,488)
Balance at end of period (in shares) at Sep. 30, 2021		0	0	8,357,391
Balance at end of period at Sep. 30, 2021	$ 94,124	$ 0	$ 0	$ 83	$ (114)	$ 184,935	$ (90,780)