Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 1,750	$ 4,011
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Stock-based compensation	4,257	1,737
Depreciation and other amortization expense	1,619	972
Amortization of acquired intangible	407
Amortization of premium on investments	741	409
Amortization of warrant issuance costs	11	55
Changes in operating assets and liabilities:
Disbursement prefunding	(6,412)	834
Customer funds receivable	(8,685)	(38,138)
Prepaid expenses and other current assets	(918)	651
Other assets	235	84
Customer liabilities	10,601	15,106
Accounts payable and accrued expenses	767	1,009
Other non-current liabilities	1,420	4
Net cash provided by (used in) operating activities	5,793	(13,266)
Cash flows from investing activities:
Purchase of property, equipment and software	(4,460)	(798)
Purchase of short-term investments	(81,089)	(60,939)
Proceeds from sales and maturities of short-term investments	77,167	24,055
Cash paid in business combination, net of cash received	(8,874)
Change in restricted cash	(3,153)	(1,014)
Net cash used in investing activities	(20,409)	(38,696)
Cash flows from financing activities:
Proceeds from exercise of common stock options	1,759	535
Excess tax benefit related to stock-based compensation	15
Net repayments under line of credit		9,000
Proceeds from initial public offering, net of costs		88,422
Net cash provided by financing activities	1,774	97,957
Net increase (decrease) in cash and cash equivalents	(12,842)	45,995
Cash and cash equivalents, beginning of period	110,979	45,077
Cash and cash equivalents, end of period	98,137	91,072
Supplemental disclosures of cash flow information:
Cash paid for taxes	2	2
Cash paid for interest	474	706
Holdback liability in connection with acquisition of BlueKite, LTD	1,500
Issuance of common stock equity in connection with acquisition of BlueKite, LTD	4,470
Purchases of property and equipment in accounts payable and accrued expenses	1,220	123
Deferred offering costs not yet paid		$ 9