Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (17,888)	$ (43,107)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	482	499
Non-cash lease expense	183	46
Change in fair value of common stock warrant liability	(2)	(133)
Change in fair value of Clene Nanomedicine contingent earn-out	(8,253)	16,970
Change in fair value of Initial Shareholders contingent earn-out	(1,054)	1,729
Stock-based compensation expense	4,386	7,520
Gain on extinguishment of notes payable	0	(647)
Gain on termination of lease	(420)	0
Accretion of debt discount	442	0
Non-cash interest expense	72	389
Changes in operating assets and liabilities:
Accounts receivable	49	(48)
Inventory	(66)	137
Prepaid expenses and other current assets	(989)	(1,528)
Accounts payable	1,528	565
Accrued liabilities	(1,044)	125
Deferred income tax	0	(119)
Operating lease obligations	(240)	(111)
Net cash used in operating activities	(22,814)	(17,713)
Cash flows from investing activities:
Purchases of marketable securities	(24,549)	0
Proceeds from maturity of marketable securities	2,500	0
Proceeds from sale of marketable securities	3,016	0
Purchases of property and equipment	(1,824)	(420)
Net cash used in investing activities	(20,857)	(420)
Cash flows from financing activities:
Proceeds from exercise of stock options	284	108
Payments of finance lease obligations	(65)	(83)
Proceeds from the issuance of notes payable	694	15,000
Payments of debt issuance costs	(30)	(471)
Payments of notes payable	0	(5)
Proceeds from the private placement	0	9,250
Payment of deferred offering costs	(100)	(1,901)
Net cash provided by financing activities	783	21,898
Effect of foreign exchange rate changes on cash and restricted cash	(147)	(33)
Net increase (decrease) in cash, cash equivalents and restricted cash	(43,035)	3,732
Cash, cash equivalents and restricted cash beginning of period	50,346	59,275
Cash, cash equivalents and restricted cash end of period	7,311	63,007
Reconciliation of cash, cash equivalents and restricted cash to the consolidated balance sheets
Cash and cash equivalents	7,253	63,007
Restricted cash	58	0
Cash, cash equivalents and restricted cash	7,311	63,007
Supplemental disclosure of non-cash investing and financing activities:
Lease liability arising from obtaining right-of-use assets, leasehold improvements, and lease incentives	2,343	0
Lease incentive realized	500	0
Lease liability settled through termination of lease	602	0
Reclassification of common stock warrant liability to permanent equity	305	0
Purchases of property and equipment in accounts payable	1,075
Common stock warrant liability recorded at issuance of notes payable		1,457
Supplemental disclosure:
Cash paid for interest expense	$ 1,013	$ 188