Equity Award Plans - Stock Option Activity for All Plans (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 28, 2017 USD ($) $ / shares shares
Stock option activity for all plans
Outstanding Stock Options, Beginning balance | shares	720
Outstanding Stock Options, Granted | shares	451
Outstanding Stock Options, Exercised | shares	(2)
Outstanding Stock Options, Forfeited | shares	(64)
Outstanding Stock Options, Expired | shares	(150)
Outstanding Stock Options, Ending balance | shares	955
Outstanding Stock Options, Exercisable | shares	273
Weighted Average Exercise Price, Beginning balance | $ / shares	$ 16.00
Weighted Average Exercise Price, Granted | $ / shares	7.16
Weighted Average Exercise Price, Exercised | $ / shares	3.52
Weighted Average Exercise Price, Forfeited | $ / shares	15.62
Weighted Average Stock Price, Expired | $ / shares	17.19
Weighted Average Exercise Price, Ending balance | $ / shares	11.68
Weighted Average Exercise Price, Exercisable | $ / shares	$ 16.26
Weighted Average Remaining Life, Outstanding	8 years 3 months 18 days
Weighted Average Remaining Life, Exercisable	7 years 1 month 6 days
Aggregate Intrinsic Value, Ending balance | $	$ 2
Aggregate Intrinsic Value, Exercisable | $	$ 1