Stockholders' Equity and Stock-Based Compensation - Assumptions to Value Stock Options (Detail) - USD ($)	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Assumptions:
Risk-free interest rates	1.60%	1.70%	1.20%
Expected life (in years)	4 years 8 months 15 days	5 years 4 months 6 days	4 years 4 months 24 days
Expected volatility	37.80%	38.60%	41.40%
Dividend yield	$ 0	$ 0	$ 0
Employee stock purchase plan [Member]
Assumptions:
Risk-free interest rates	0.34%	0.10%	0.08%
Expected life (in years)	6 months	6 months	6 months
Expected volatility	27.20%	27.40%	30.00%
Dividend yield	$ 0	$ 0	$ 0