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Note 3 - Acquisition of Astero Bio Corporation - Fair Value of Net Assets Acquired (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Jun. 30, 2019	Apr. 01, 2019	Dec. 31, 2018
Goodwill, Ending Balance		$ 9,524,000
Astero [Member]
Cash and cash equivalents		12,000
Accounts receivable		154,000
Inventory		456,000
Goodwill, Ending Balance		9,524,000	$ 9,500,000
Other assets		100,000
Accounts Payable		(251,000)
Other liabilities		(164,000)
Fair value of net assets acquired		14,381,000
Identifiable intangible assets	$ 4,550,000
Astero [Member] \| Customer Relationships [Member]
Intangible assets		160,000
Identifiable intangible assets	$ 160,000
Identifiable intangible assets useful life (Year)	4 years
Astero [Member] \| Trade Names [Member]
Intangible assets		470,000
Identifiable intangible assets	$ 470,000
Identifiable intangible assets useful life (Year)	9 years
Astero [Member] \| Developed Technology Rights [Member]
Intangible assets		$ 3,920,000
Identifiable intangible assets	$ 3,920,000
Astero [Member] \| Developed Technology Rights [Member] \| Minimum [Member]
Identifiable intangible assets useful life (Year)	5 years
Astero [Member] \| Developed Technology Rights [Member] \| Maximum [Member]
Identifiable intangible assets useful life (Year)	9 years