Note 8 - Leases (Details Textual) $ in Thousands	1 Months Ended			3 Months Ended
	Oct. 31, 2021 USD ($)	Oct. 31, 2019 USD ($)	Oct. 31, 2014 USD ($) ft²	Mar. 31, 2024 USD ($)		Dec. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022	Feb. 28, 2019	Jan. 01, 2019 USD ($)
Restricted Cash				$ 1,289			$ 1,276
Operating Lease, Liability				10,343	[1]	$ 10,677
Operating Lease, Right-of-Use Asset				$ 7,906		$ 8,050
Lessee, Operating Lease, Remaining Lease Term (Month)				2 years
Operating Lease, Weighted Average Remaining Lease Term (Year)				5 years 9 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent				10.01%					10.25%
Operating Lease, Payments				$ 600
Minimum [Member]
Lessee, Operating Lease, Remaining Lease Term (Month)				9 months
Maximum [Member]
Lessee, Operating Lease, Remaining Lease Term (Month)				7 years
Leased Office Space [Member]
Operating Lease, Liability				$ 10,300						$ 9,500
Operating Lease, Right-of-Use Asset				7,900						$ 8,100
The New Jersey Lease [Member]
Average Annual Rental Payments		$ 300
Operating Lease, Expense				100
The North Carolina Lease [Member]
Lessee, Operating Lease, Term of Contract (Year)	5 years
Average Annual Rental Payments	$ 200
Operating Lease, Expense				$ 100
Operating Lease, Weighted Average Discount Rate, Percent								5.65%
Office Agreement with Fortress Biotech [Member]
Percentage of Occupancy			45.00%
Area of Real Estate Property (Square Foot) | ft²			24,000
Lessee, Operating Lease, Term of Contract (Year)			15 years
Average Annual Rental Payments			$ 1,800
Office Agreement with Fortress Biotech [Member] | Deposit for Office Agreement [Member]
Restricted Cash			$ 1,300
Office Agreement [Member]
Lessee, Operating Lease, Renewal Term (Year)						5 years

[1] As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date and considering the term of the lease to determine the present value of lease payments. We used the incremental borrowing rate of 10.25% on February 28, 2019, for operating leases that commenced prior to that date through December 31, 2021. We used an incremental borrowing rate of 5.65% for the NC lease.