Note 3 - Acquisitions (Details Textual) - USD ($)	Oct. 01, 2020	Sep. 30, 2020	Mar. 31, 2021	Dec. 31, 2020
Goodwill, Ending Balance			$ 58,449,000	$ 58,449,000
SciSafe Holdings, Inc [Member]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage	100.00%
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	611,683
Business Acquisition, Share Price (in dollars per share)	$ 29.29
Payments to Acquire Businesses, Gross	$ 15,000,000
Business Acquisition, Amount Held in Escrow	1,500,000
Business Combination, Contingent Consideration, Liability, Total	3,700,000		$ 6,400,000	$ 6,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tangible Assets	2,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities	3,297,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	12,100,000
Goodwill, Ending Balance	24,943,000
Payments to Acquire Notes Receivable		$ 500,000
Business Combination, Indemnification Assets, Amount as of Acquisition Date	$ 130,000
SciSafe Holdings, Inc [Member] | Maximum [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	626,000