CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 8,437	$ 1,575
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,055	5,997
Amortization of premium on investments	868	733
Provision for uncollectible accounts	593	423
Excess tax benefit from stock-based awards	(6,432)	(1,281)
Deferred income tax	(819)	(399)
Increase in fair value of contingent consideration	224	304
Stock-based compensation expense	7,916	6,694
Loss on interest rate derivative contract	73	364
Changes in operating assets and liabilities:
Accounts receivable	(7,650)	(2,347)
Prepaid expenses and other current assets	5,985	(584)
Other long-term assets	166	277
Accounts payable	781	128
Accrued expenses	388	(896)
Deferred revenue	4,887	4,866
Deferred rent	(3,303)	(614)
Net cash provided by operating activities	20,169	15,240
CASH FLOWS FROM INVESTING ACTIVITIES:
Capitalized software development costs	(3,068)	(1,579)
Purchases of property and equipment	(6,841)	(9,870)
Proceeds from sale or disposal of equipment		363
Proceeds from sales and maturities of investments	86,834	50,450
Purchases of short-term and long-term investments	(80,175)	(60,372)
Payments for acquisition	(6,988)
Decrease in restricted cash	2,887	331
Net cash used in investing activities	(7,351)	(20,677)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock under stock plans	4,558	3,425
Excess tax benefit from stock-based awards	6,432	1,281
Payment of contingent consideration accrued at acquisition date	(2,558)
Payment to terminate interest rate derivative contract	(563)
Payments on long-term debt and capital lease obligations	(9,216)	(1,786)
Net cash (used in) provided by financing activities	(1,347)	2,920
Effects of exchange rate changes on cash and cash equivalents	(45)	(64)
Net increase in cash and cash equivalents	11,426	(2,581)
Cash and cash equivalents at beginning of period	35,944	30,526
Cash and cash equivalents at end of period	47,370	27,945
Supplemental disclosures of non-cash items - Property and equipment recorded in accounts payables and accrued expenses	222	273
Supplemental disclosures - Cash paid for interest	225	284
Supplemental disclosures - Cash paid for taxes	804	1,389
Property and equipment acquired under capital leases		$ 363