Note 8 - Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Year Ended December 31,
	2014		2013		2012
Options to purchase common stock		3,489		3,830		3,746
Restricted stock units		213		173		97
Employee stock purchase plan shares		86		72		78
Performance stock units		37		34		8
Total		3,825		4,109		3,929