Note 2 - Summary of Significant Accounting Policies - Outstanding Stock Options and Stock Warrants Excluded from the Diluted Net Loss Per Share Computation (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Employee Stock Option [Member]
Period end stock options to purchase common stock (in shares)	297	348	297	348
Warrant [Member]
Period end stock options to purchase common stock (in shares)	3,495	1,071	3,495	1,071
Period end stock options to purchase common stock (in shares)	3,792	1,419	3,792	1,419