Note 4 - Fair Value Measurements - Remeasurement of Fair Value Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Convertible Preferred Stock Warrant Liability [Member]
Fair value, period end	$ 275
Change in fair value	(250)
Exchange of convertible preferred stock warrants	(25)
Fair value, period end	0
Maturity Date Preferred Stock Warrant Liability [Member]
Fair value, period end	10
Change in fair value	(10)
Fair value, period end	0
Convertible Shareholder Note Derivative Liability [Member]
Fair value, period end	1,044
Change in fair value	1,224
Conversion of convertible notes	(2,268)
Fair value, period end	$ 0