CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities
Net income	$ 487	$ 682
Reconciliation of net income to net cash provided by operating activities
Deferred income taxes	31	364
Depreciation and amortization of property and equipment	2,353	1,244
Amortization of intangible assets	1,434	520
Provision for doubtful accounts	185	164
Stock-based compensation	2,035	1,327
Changes in assets and liabilities
Accounts receivable	(951)	(1,235)
Deferred costs	(1,265)	(1,136)
Prepaid expenses and other current assets	2,512	157
Accounts payable	(207)	533
Accrued compensation and benefits	473	(312)
Accrued expenses and other current liabilities	497	463
Deferred revenue	1,049	1,800
Net cash provided by operating activities	8,633	4,571
Cash flows from investing activities
Purchases of property and equipment	(1,737)	(1,890)
Net cash used in investing activities	(1,737)	(1,890)
Cash flows from financing activities
Net proceeds from exercise of options to purchase common stock	1,597	811
Excess tax benefit from exercise of options to purchase common stock	40	24
Net proceeds from employee stock purchase plan	551
Net cash provided by financing activities	2,188	835
Net increase in cash and cash equivalents	9,084	3,516
Cash and cash equivalents at beginning of period	66,050	31,985
Cash and cash equivalents at end of period	$ 75,134	$ 35,501