Income Taxes (Components of Deferred Tax Assets) (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets, Net [Abstract]
Net operating loss carry-forwards	$ 46,591	$ 42,525
Capitalized research and development	21,431	19,103
Stock-based compensation	2,083	3,192
Depreciation and amortization	856	929
Lease accounting	13,899	13,660
Other	1,907	1,452
Total deferred tax assets before valuation allowance	86,767	80,861
Less: valuation allowance	(75,166)	(68,818)
Total deferred tax assets after valuation allowance	11,601	12,043
Deferred Tax Liabilities, Net [Abstract]
Right-of-use asset	(11,510)	(12,043)
In-process research and development	(3,077)	(3,077)
Other	(91)
Total deferred tax liabilities	14,678	15,120
Net deferred tax liability	$ (3,077)	$ (3,077)