Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Revenue, net
Direct	$ 35,681		$ 34,215		$ 113,873		$ 109,048
Fulfillment partner	265,745		221,137		792,751		648,207
Total net revenue	301,426		255,352		906,624		757,255
Cost of goods sold
Direct	30,777	[1]	30,684	[1]	99,768	[1]	99,422	[1]
Fulfillment partner	211,499		178,126		630,931		520,614
Total cost of goods sold	242,276		208,810		730,699		620,036
Gross profit	59,150		46,542		175,925		137,219
Operating expenses:
Sales and marketing	22,463	[1]	14,899	[1]	60,376	[1]	42,886	[1]
Technology	17,259	[1]	16,085	[1]	53,339	[1]	46,845	[1]
General and administrative	15,970	[1]	13,828	[1]	47,643	[1]	43,166	[1]
Restructuring	0		(45)		(471)		53
Total operating expenses	55,692		44,767		160,887		132,950
Operating income	3,458		1,775		15,038		4,269
Interest income	34		30		100		86
Interest expense	(33)		(194)		(121)		(655)
Other income, net	165		1,213		360		2,364
Income before income taxes	3,624		2,824		15,377		6,064
Provision for income taxes	91		131		449		182
Net income	3,533		2,693		14,928		5,882
Net income per common share—basic:
Net income attributable to common shares-basic (in dollars per share)	$ 0.15		$ 0.11		$ 0.63		$ 0.25
Weighted average common shares outstanding-basic (in shares)	23,766		23,447		23,692		23,382
Net income per common share—diluted:
Net income attributable to common shares-diluted (in dollars per share)	$ 0.14		$ 0.11		$ 0.61		$ 0.25
Weighted average common shares outstanding-diluted (in shares)	24,446		23,754		24,297		23,511
Comprehensive income	$ 3,533		$ 2,693		$ 14,928		$ 5,882

[1] (1) Includes stock-based compensation as follows (Note 7): Cost of goods sold — direct $37 $74 $117 $200 Sales and marketing 44 108 123 260 Technology 33 218 235 585 General and administrative 695 580 1,902 1,579 Total $809 $980 $2,377 $2,624