Note 5 - Revenue 1 (Details Textual) - USD ($)	3 Months Ended		9 Months Ended		37 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 28, 2018	Dec. 31, 2018	Sep. 30, 2015
Revenue from Contract with Customer, Including Assessed Tax	$ 454,000	$ 281,000	$ 5,946,000	$ 2,392,000
Contract with Customer, Asset, Net, Current, Total	204,000		204,000			$ 0
Contract With Customer, Asset, Revenue Recognized	0		0			$ 0
Revenue, Remaining Performance Obligation, Not Recorded on Balance Sheet	413,000		413,000
Income Tax Expense (Benefit), Total	31,000		$ 294,000	29,000
Foreign Tax Authority [Member] | National Tax Agency, Japan [Member]
Royalty Withholding Tax			5.00%
Income Tax Expense (Benefit), Total	17,000			29,000
Customer Service Contracts [Member]
Revenue from Contract with Customer, Including Assessed Tax	94,000		$ 94,000
Government Contract [Member]
Revenue from Contract with Customer, Including Assessed Tax		194,000		1,324,000
Contract Value					$ 15,700,000		$ 14,000,000
Contract Value, Adjustment					$ 1,700,000
Revenues, Total		194,000		1,324,000
Royalty [Member]
Revenue from Contract with Customer, Including Assessed Tax	8,000	87,000	3,736,000	1,050,000
Royalty [Member] | GSK Research and License Agreement [Member]
Revenue from Contract with Customer, Including Assessed Tax	8,000	87,000	$ 772,000	$ 498,000
Royalty Percentage			7.00%	7.00%
Royalty [Member] | Daiichi Sankyo Collaberation and License Agreement [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	$ 0	$ 2,964,000	$ 552,000
Royalty Percentage			4.00%	4.00%
Royalty [Member] | Daiichi Sankyo Collaberation and License Agreement [Member] | HealthCare Royalty Partners III, L.P. [Member]
Liability Related to Sale of Future Royalties	$ 335,000		$ 335,000