CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue:
Hardware revenue	$ 41,415	$ 44,307	$ 16,377
Total net revenue	2,214,253	1,708,721	1,267,118
Cost of Revenue [Abstract]
Hardware costs	62,393	68,562	30,874
Amortization of acquired technology	6,544	8,028	5,639
Total cost of revenue	1,374,947	1,132,683	897,088
Gross profit	839,306	576,038	370,030
Operating expenses:
Product development	321,888	268,537	199,638
Sales and marketing	253,170	173,876	145,618
General and administrative	250,553	251,993	143,466
Transaction, loan and advance losses	67,018	51,235	54,009
Amortization of acquired customer assets	883	850	1,757
Total operating expenses	893,512	746,491	544,488
Operating loss	(54,206)	(170,453)	(174,458)
Interest and other (income) expense, net	8,458	(780)	1,613
Loss before income tax	(62,664)	(169,673)	(176,071)
Provision for income taxes	149	1,917	3,746
Net loss	(62,813)	(171,590)	(179,817)
Deemed dividend on Series E preferred stock	0	0	(32,200)
Net loss attributable to common stockholders	$ (62,813)	$ (171,590)	$ (212,017)
Net loss per share attributable to common stockholders:
Basic (in USD per share)	$ (0.17)	$ (0.50)	$ (1.24)
Diluted (in USD per share)	$ (0.17)	$ (0.50)	$ (1.24)
Weighted-average shares used to compute net loss per share attributable to common stockholders:
Basic (in shares)	379,344	341,555	170,498
Diluted (in shares)	379,344	341,555	170,498
Subscription and services-based
Revenue:
Revenue	$ 252,664	$ 129,351	$ 58,013
Cost of Revenue [Abstract]
Transaction and services-based costs	75,720	43,132	22,470
Customers Other than Starbucks | Transaction-based
Revenue:
Revenue	1,920,174	1,456,160	1,050,445
Cost of Revenue [Abstract]
Transaction and services-based costs	1,230,290	943,200	672,667
Starbucks | Transaction-based
Revenue:
Revenue	0	78,903	142,283
Cost of Revenue [Abstract]
Transaction and services-based costs	$ 0	$ 69,761	$ 165,438