Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2013 Certificates_of_Deposits	Sep. 30, 2012	Sep. 30, 2011
Property, Plant and Equipment [Line Items]
Deferred rent	$ 367,000	$ 434,000
Number of certificates of deposit	2
Restricted short-term investment expiration year	2013
Restricted long-term investment expiration year	2018
Returns policy, minimum compared to expiration data	Wholesale customers can return purchased product during an 18-month period that begins six months prior to the product's expiration date
Returns policy, maximum compared to expiration data	Wholesale customers can return purchased product during an 18-month period that ends 12 months after the expiration date.
Right of replacement, notice period to the Company after receipt of the product	30 days
Estimated dividend yield	0.00%	0.00%	0.00%
Advertising costs	8,900,000	7,300,000	5,700,000
Uncertain income tax position, description	Less than a 50% likelihood of being sustained
Unrecognized tax benefit, decrease in deferred tax assets and valuation allowance	3,600,000
Accrued for interest and penalties	$ 0	$ 0
Computer equipment and related software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Computer equipment and related software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Office equipment, furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Manufacturing equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	8 years