Note 18 - Subsequent Events (Details Textual)		3 Months Ended	12 Months Ended
	Mar. 24, 2022 $ / shares	Mar. 24, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) shares	Mar. 04, 2022 ft²	Feb. 03, 2022 USD ($)
Stock Issued During Period, Value, New Issues				$ 10,839,000
At The Market Offering Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares				2,620,652
Stock Issued During Period, Value, New Issues			$ 6,832,000
Proceeds from Issuance of Common Stock				$ 8,224,000
Payments of Stock Issuance Costs				$ 493,000
Subsequent Event [Member]
Market Offering, Additional Shares, Maximum Amount						$ 4,275,000
Subsequent Event [Member] | Lease Agreement with Z3 Investment LLC [Member]
Area of Real Estate Property (Square Foot) | ft²					35,475
Lessee, Lease, Number of Extensions					2
Lessee, Operating Lease, Renewal Term (Year)					5 years
Subsequent Event [Member] | Boyalife License Agreement [Member]
Royalty, Percentage of Annual Net Sales Covered by Patents	7.50%
Royalty, Percentage of Annual Net Sales on Covered Intellectual Property	5.00%
Subsequent Event [Member] | Boyalife License Agreement [Member] | ImmuneCyte [Member]
Ownership Percentage Transferred as Consideration	8.63%
Subsequent Event [Member] | Convertible Promissory Note [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares	$ 0.65	$ 0.65
Subsequent Event [Member] | At The Market Offering Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares		918,093
Stock Issued During Period, Value, New Issues		$ 681,000
Shares Issued, Price Per Share (in dollars per share) | $ / shares	$ 0.74	$ 0.74
Proceeds from Issuance of Common Stock		$ 594,000
Payments of Stock Issuance Costs		$ 87,000
Subsequent Event [Member] | Minimum [Member]
Market Offering Agreement, Maximum Amount						15,280,313
Subsequent Event [Member] | Maximum [Member]
Market Offering Agreement, Maximum Amount						$ 19,555,261