Note 6 - Stockholders' Equity - Activity Under the Equity Incentive Plans (Details) shares in Thousands	3 Months Ended
	Dec. 31, 2017 $ / shares shares
Outstanding, beginning balance (in shares) | shares	4,450
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 3.01
Granted (in shares) | shares	47
Granted (in dollars per share) | $ / shares	$ 1.81
Exercised/Released (in shares) | shares	(4)
Exercised/Released (in dollars per share) | $ / shares
Cancelled (in shares) | shares	(207)
Cancelled (in dollars per share) | $ / shares	$ 4.81
Outstanding, ending balance (in shares) | shares	4,286
Outstanding, ending balance (in dollars per share) | $ / shares	$ 2.91
Vested and expected to vest (in shares) | shares	4,108
Vested and expected to vest (in dollars per share) | $ / shares	$ 2.94
Restricted Stock Units (RSUs) [Member]
Outstanding, beginning balance (in shares) | shares	89
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 3.96
Granted (in shares) | shares	224
Granted (in dollars per share) | $ / shares	$ 1.81
Exercised/Released (in shares) | shares	(11)
Exercised/Released (in dollars per share) | $ / shares	$ 5.66
Cancelled (in shares) | shares	(1)
Cancelled (in dollars per share) | $ / shares	$ 5.80
Outstanding, ending balance (in shares) | shares	301
Outstanding, ending balance (in dollars per share) | $ / shares	$ 2.30