Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue:
Total revenue	$ 35	$ 201	$ 65	$ 414
Operating expenses:
Cost of revenue	0	555	0	798
Research and development	9,166	6,472	17,746	12,747
General and administrative	4,464	6,949	9,250	12,339
Total operating expenses	13,630	13,976	26,996	25,884
Loss from operations	(13,595)	(13,775)	(26,931)	(25,470)
Other income (expense), net:
Interest expense	(751)	(26)	(1,533)	(577)
Gain on extinguishment of notes payable	0	0	0	647
Gain on termination of lease	0	0	420	0
Change in fair value of common stock warrant liability	20	133	2	133
Change in fair value of Clene Nanomedicine contingent earn-out	8,310	8,640	8,253	(16,970)
Change in fair value of Initial Shareholders contingent earn-out	1,066	1,232	1,054	(1,729)
Australia research and development credit	356	375	655	714
Other income (expense), net	60	(2)	192	1
Total other income (expense), net	9,061	10,352	9,043	(17,781)
Net loss before income taxes	(4,534)	(3,423)	(17,888)	(43,251)
Income tax benefit	0	72	0	144
Net loss	(4,534)	(3,351)	(17,888)	(43,107)
Other comprehensive loss:
Unrealized loss on available-for-sale securities	(37)	0	(87)	0
Foreign currency translation adjustments	(110)	(61)	(60)	(37)
Total other comprehensive loss	(147)	(61)	(147)	(37)
Comprehensive loss	$ (4,681)	$ (3,412)	$ (18,035)	$ (43,144)
Net loss per share-- basic	$ (0.07)	$ (0.05)	$ (0.28)	$ (0.71)
Net loss per share-- diluted	$ (0.07)	$ (0.05)	$ (0.28)	$ (0.71)
Weighted average common shares used to compute basic net loss per share	63,335,271	61,165,018	63,095,400	60,919,340
Weighted average common shares used to compute diluted net loss per share	63,335,271	61,165,018	63,095,400	60,919,340
Product revenue
Revenue:
Total revenue	$ 2	$ 138	$ 9	$ 337
Royalty revenue
Revenue:
Total revenue	$ 33	$ 63	$ 56	$ 77