Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income (loss)	$ (3,599)	$ 1,750
Adjustments to reconcile net income to net cash used in operating activities:
Stock-based compensation	6,485	4,257
Depreciation And Amortization	2,368	1,619
Amortization of acquired intangible	407	407
Loss on disposal of property equipment and software	39
Amortization of net premium on investments	420	741
Amortization of warrant issuance costs	11	11
Changes in operating assets and liabilities:
Disbursement prefunding	28,273	(6,412)
Customer funds receivable	(6,880)	(8,685)
Prepaid expenses and other current assets	(1,828)	(918)
Other assets	(40)	235
Customer liabilities	8,276	10,601
Accounts payable and accrued expenses	3,066	767
Non-current liabilities	403	1,420
Net cash provided by operating activities	37,401	5,793
Cash flows from investing activities:
Purchase of property, equipment, software, and intangible assets	(2,249)	(4,460)
Purchase of short-term investments	(61,761)	(81,089)
Proceeds from sales and maturities of short-term investments	67,764	77,167
Cash paid in business combination, net of cash received		(8,874)
Change in restricted cash	(433)	(3,153)
Net cash provided by (used in) investing activities	3,321	(20,409)
Cash flows from financing activities:
Proceeds from exercise of common stock options	2,458	1,759
Excess tax benefit related to stock-based compensation		15
Taxes paid related to net share settlement	(783)
Net borrowings (repayments) under line of credit	(28,000)
Net cash provided by (used in) financing activities	(26,325)	1,774
Net increase (decrease) in cash and cash equivalents	14,397	(12,842)
Cash and cash equivalents, beginning of period	67,216	110,979
Cash and cash equivalents, end of period	81,613	98,137
Supplemental disclosures of cash flow information:
Cash paid for taxes	120	2
Cash paid for interest	506	474
Cash received from refund of income taxes	17
Supplemental disclosure of non-cash investing and financing activities:
Change in the Business Combination Contingent Consideration Liability		1,500
Issuance of common stock in connection with acquisition of BlueKite, LTD		4,470
Purchases of property and equipment in accounts payable and accrued expenses	$ 80	$ 1,220