Note 1 - Description of Business and Basis of Presentation (Details Textual)				3 Months Ended		6 Months Ended
		Jun. 04, 2019	Apr. 18, 2019 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) shares	Mar. 31, 2019 USD ($)	Jun. 30, 2019 USD ($) shares	Jan. 01, 2019	Dec. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance				$ 778,000		$ 778,000		$ (1,711,000)
Reorganization of Subsidiary and Related Change in Non-controlling Interest
Common Stock, Shares Authorized | shares				350,000,000		350,000,000		350,000,000
Class of Warrant or Right, Issued During Period | shares	[1]					444,445
Cash and Cash Equivalents, at Carrying Value, Ending Balance				$ 2,424,000		$ 2,424,000		$ 2,400,000
Working Capital				3,374,000		3,374,000
Retained Earnings (Accumulated Deficit), Ending Balance				(230,603,000)		(230,603,000)		$ (227,435,000)
April 2019 Pre-funded Warrants [Member]
Class of Warrant or Right, Issued During Period | shares			444,445
Warrants Issued, Price Per Warrant | $ / shares			$ 1.70
Proceeds from Issuance of Warrants			$ 756,000
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares			1
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares			$ 0.10
April 2019 Pre-funded Warrants [Member] | Minimum [Member]
Class of Warrant or Right, Maximum Percentage of Outstanding Stock Ownership Limitation			4.99%
April 2019 Pre-funded Warrants [Member] | Maximum [Member]
Class of Warrant or Right, Maximum Percentage of Outstanding Stock Ownership Limitation			9.99%
Boyalife Investment Fund II, Inc. [Member] | Revolving Credit Facility [Member]
Long-term Line of Credit, Total				8,713,000		8,713,000
Line of Credit Facility, Maximum Borrowing Capacity				10,000,000		10,000,000			$ 10,000,000
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio		10
Noncontrolling Interest [Member]
Reorganization of Subsidiary and Related Change in Non-controlling Interest				2,843,000	$ 2,843,000
ThermoGenesis [Member]
Ownership in Subsidiary Exchanged							20.00%
Noncontrolling Interest, Ownership Percentage by Parent							100.00%
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance				(1,711,000)		(1,711,000)
CAR-TXpress [Member]
Minority Interest Acquired Through Exchange							20.00%
Noncontrolling Interest, Ownership Percentage by Parent							80.00%
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance				$ 1,100,000		$ 1,100,000

[1] See Footnote 1 of the Notes to the Condensed Consolidated Financial Statements.