Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Jan. 30, 2016	Jan. 31, 2015	Feb. 01, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 91,103,000	$ 91,002,000	$ 18,195,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	44,595,000	34,463,000	27,654,000
Impairment of long-lived assets	0	0	1,385,000
Amortization of purchase premiums and accretion of purchases discount—net	1,166,000
Amortization of debt discount	22,114,000	7,969,000
Excess tax benefit from exercise of stock options	(10,443,000)	(16,421,000)	(3,685,000)
Stock-based compensation expense	24,223,000	17,072,000	67,622,000
Deferred income taxes	(6,011,000)	2,693,000	5,602,000
Other non-cash interest expense	2,473,000	1,342,000	671,000
Change in assets and liabilities:
Accounts receivable	(2,629,000)	(3,991,000)	(4,995,000)
Merchandise inventories	(166,505,000)	(106,036,000)	(100,937,000)
Prepaid expense	8,929,000	15,123,000	(22,819,000)
Other current assets	1,888,000	(6,030,000)	(3,129,000)
Accounts payable and accrued expenses	44,378,000	25,470,000	57,318,000
Deferred revenue and customer deposits	33,213,000	19,955,000	8,750,000
Other current liabilities	39,580,000	(3,131,000)	28,883,000
Deferred rent and lease incentives	13,597,000	3,574,000	7,196,000
Other non-current obligations	215,000	(563,000)	(190,000)
Net cash provided by operating activities	141,886,000	82,491,000	87,521,000
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(119,461,000)	(110,359,000)	(93,868,000)
Acquisition of buildings and land	(13,999,000)
Construction related deposits	(20,049,000)	(9,250,000)
Purchase of trademarks and domain names	(339,000)	(453,000)
Purchase of investments	(217,379,000)	(91,604,000)
Maturities of investments	143,830,000	11,118,000
Net cash used in investing activities	(227,397,000)	(200,548,000)	(93,868,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Gross borrowings under revolving line of credit		749,945,000	1,670,876,000
Gross repayments under revolving line of credit		(835,370,000)	(1,667,952,000)
Revolving line of credit deferred financing fees		(2,133,000)
Proceeds from issuance of convertible senior notes	296,250,000	350,000,000
Proceeds from issuance of warrants	30,390,000	40,390,000
Purchase of convertible note hedges	(68,250,000)	(73,325,000)
Debt issuance costs related to convertible senior notes	(2,382,000)	(5,385,000)
Borrowings under build-to-suit lease transactions		1,776,000
Payments on capital leases	(248,000)	(1,803,000)	(2,555,000)
Proceeds from exercise of stock options	25,606,000	16,400,000	7,629,000
Excess tax benefit from exercise of stock options	10,443,000	16,421,000	3,685,000
Tax withholdings related to issuance of stock-based awards	(5,027,000)	(3,116,000)	(178,000)
Net cash provided by financing activities	286,782,000	253,800,000	11,505,000
Effects of foreign currency exchange rate translation	(308,000)	(198,000)	(123,000)
Net increase in cash and cash equivalents	200,963,000	135,545,000	5,035,000
Cash and cash equivalents
Beginning of period	148,934,000	13,389,000	8,354,000
End of period	349,897,000	148,934,000	13,389,000
Cash paid for interest	13,369,000	8,611,000	5,038,000
Cash paid for taxes	29,135,000	60,121,000	1,521,000
Non-cash transactions:
Property and equipment additions due to build-to-suit lease transactions	96,323,000	89,829,000	33,494,000
Property and equipment reduction due to effected sale leaseback (Note 5)	(74,855,000)
Property and equipment additions from use of construction related deposits	13,915,000
Property and equipment additions in accounts payable and accrued expenses at period-end	12,108,000	10,875,000	4,204,000
Property and equipment acquired under capital lease	88,000	38,000	238,000
Building acquired under capital lease		6,798,000
Issuance of non-current notes payable related to share repurchases from former employees	238,000	$ 16,575,000	$ 2,710,000
Trademarks and Domain Names [Member]
Non-cash transactions:
Property and equipment additions in accounts payable and accrued expenses at period-end	$ 107,000