Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue:
Total revenue	$ 73	$ 107
Operating expenses:
Cost of revenue	16	5
Research and development	5,869	7,395
General and administrative	3,420	3,439
Total operating expenses	9,305	10,839
Loss from operations	(9,232)	(10,732)
Other income (expense), net:
Interest income	359	172
Interest expense	(1,244)	(1,066)
Commitment share expense	0	(399)
Change in fair value of common stock warrant liabilities	(1,309)	0
Change in fair value of Clene Nanomedicine contingent earn-out liability	53	(55)
Change in fair value of Initial Stockholders contingent earn-out liability	7	(7)
Research and development tax credits and unrestricted grants	286	314
Other income, net	0	3
Total other income (expense), net	(1,848)	(1,038)
Net loss before income taxes	(11,080)	(11,770)
Income tax benefit	0	0
Net loss	(11,080)	(11,770)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities	(4)	14
Foreign currency translation adjustments	(55)	4
Total other comprehensive income (loss)	(59)	18
Comprehensive loss	$ (11,139)	$ (11,752)
Net loss per share – basic and diluted (in dollars per share)	$ (0.09)	$ (0.15)
Weighted average common shares used to compute basic and diluted net loss per share (in shares)	128,427,231	76,049,665
Product [Member]
Revenue:
Total revenue	$ 44	$ 64
Royalty [Member]
Revenue:
Total revenue	$ 29	$ 43