Note 4 - Stockholders' Equity - Stock Options Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Outstanding, January 1, 2016 (in shares)	1,764
Outstanding, January 1, 2016 (in dollars per share) | $ / shares	$ 7.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	50
Exercised (in shares)	(63)
Exercised (in dollars per share) | $ / shares	$ 7.20
Canceled (in shares)	(7)
Canceled (in dollars per share) | $ / shares	$ 15.01
Expired (in shares)	(75)
Expired (in dollars per share) | $ / shares	$ 13.79
Outstanding, June 30, 2016 (in shares)	1,669
Outstanding, June 30, 2016 (in dollars per share) | $ / shares	$ 7.73
Outstanding, June 30, 2016	4 years 317 days
Outstanding, June 30, 2016 | $	$ 10,719
Vested and expected to vest, June 30, 2016 (in shares)	1,660
Vested and expected to vest, June 30, 2016 (in dollars per share) | $ / shares	$ 7.70
Vested and expected to vest, June 30, 2016	4 years 306 days
Vested and expected to vest, June 30, 2016 | $	$ 10,704
Exercisable, June 30, 2016 (in shares)	1,523
Exercisable, June 30, 2016 (in dollars per share) | $ / shares	$ 7.17
Exercisable, June 30, 2016	4 years 178 days
Exercisable, June 30, 2016 | $	$ 10,539