Note 13. Equity Incentive Plans and Employee Benefits (Detail) - Stock Option Activities and Balances of Stock Option Plans (USD $)	3 Months Ended
	Jul. 28, 2012	Apr. 28, 2012	Jan. 28, 2012
Balance	5,667,572		5,846,027
Balance (in Dollars per share)	$ 12.54		$ 12.47
Balance	5 years 262 days	6 years 10 days	6 years 58 days
Balance (in Dollars)	$ 1,163,897	$ 710,739	$ 885,840
Ending Vested and Expected to Vest	5,598,252
Ending Vested and Expected to Vest (in Dollars per share)	$ 12.47
Ending Vested and Expected to Vest	5 years 248 days
Ending Vested and Expected to Vest (in Dollars)	1,127,291
Ending Exercisable	3,946,445
Ending Exercisable (in Dollars per share)	$ 13.12
Ending Exercisable	4 years 350 days
Ending Exercisable (in Dollars)	$ 861,903
Granted	100,000
Granted (in Dollars per share)	$ 5.56
Cancelled	(84,414)	(152,654)
Cancelled (in Dollars per share)	$ 12.34	$ 11.33
Exercised	(5,201)	(25,801)
Exercised (in Dollars per share)	$ 3.23	$ 2.18
Balance	5,677,957	5,667,572
Balance (in Dollars per share)	$ 12.43	$ 12.54
Balance	5 years 262 days	6 years 10 days	6 years 58 days