Note 4 - Collaboration and License Agreement (Details Textual) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		17 Months Ended
	Nov. 06, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer, Excluding Assessed Tax, Total		$ 1,615	$ 3,789	$ 2,707	$ 4,045
Contract with Customer, Liability, Current		4,023		4,023			$ 4,571
Contract with Customer, Liability, Noncurrent		1,389		$ 1,389			3,548
Research and Development Services [Member]
Service Period (Year)				2 years
3D Medicines, Inc [Member]
Proceeds from Collaborators				$ 9,000		$ 21,000
Collaborative Agreement, Maximum Clinical Development, Regulatory and Commercial Milestone Payments	$ 207,000
Collaborative Agreement, Royalty, Period After First Commercial Sale of Product (Year)	10 years
Revenue, Remaining Performance Obligation, Amount		21,000		21,000
Revenue from Contract with Customer, Excluding Assessed Tax, Total				1,600
Contract with Customer, Liability, Total		5,400		5,400			$ 8,100
Contract with Customer, Liability, Current		4,000		4,000
Contract with Customer, Liability, Noncurrent		1,400		1,400
3D Medicines, Inc [Member] | Research and Development Services [Member]
Revenue, Remaining Performance Obligation, Amount		11,300		11,300
Revenue from Contract with Customer, Excluding Assessed Tax, Total				2,700	1,200
3D Medicines, Inc [Member] | License [Member]
Revenue, Remaining Performance Obligation, Amount		$ 9,700		$ 9,700
Revenue from Contract with Customer, Excluding Assessed Tax, Total			$ 2,800		$ 2,800