Stockholders' Equity and Stock-Based Compensation - Assumptions to Value Stock Options (Detail) (USD $)	12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 29, 2012
Assumptions:
Risk-free interest rates	1.20%	0.50%	0.70%
Expected life (in years)	4 years 4 months 24 days	4 years 4 months 24 days	4 years 3 months 24 days
Expected volatility	41.40%	43.70%	46.90%
Dividend yield	$ 0	$ 0	$ 0
Employee stock purchase plan [Member]
Assumptions:
Risk-free interest rates	0.08%	0.11%	0.16%
Expected life (in years)	6 months	6 months	6 months
Expected volatility	30.00%	32.00%	35.00%
Dividend yield	$ 0	$ 0	$ 0