Condensed Consolidated Statements of Cash Flows (unaudited) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities:
Net income	$ 9,283,000	$ 8,319,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	575,000	191,000
Stock-based compensation expense	3,018,000	2,224,000
Amortization of acquired intangible assets	37,000	363,000
Deferred taxes	2,494,000	(6,000)
Purchases of treasury stock in connection with tax withholdings on restricted stock grants	(385,000)	(181,000)
Provisions for (reversal of) doubtful accounts	(82,000)	37,000
Loss on disposal of property and equipment	3,000	6,000
Impairment of investments		216,000
Tax benefit related to stock-based compensation expense	141,000
Excess tax benefit from stock-based compensation	(79,000)
Changes in operating assets and liabilities:
Accounts receivable	7,707,000	(5,609,000)
Prepaid expenses and other assets	(2,027,000)	(448,000)
Accounts payable	(1,079,000)	62,000
Accrued compensation and related benefits	(3,622,000)	2,134,000
Accrued and other liabilities	(1,170,000)	(342,000)
Deferred revenues	(219,000)	(322,000)
Billings in excess of recognized revenues	(291,000)	(1,188,000)
Net cash provided by operating activities	14,304,000	5,456,000
Investing activities:
Purchases of property and equipment	(2,537,000)	(639,000)
Net cash used in investing activities	(2,537,000)	(639,000)
Financing activities:
Proceeds from exercise of stock options	2,810,000	894,000
Proceeds from employee stock purchase plan	546,000	468,000
Excess tax benefit from stock-based compensation	79,000
Purchases of treasury stock		(1,982,000)
Net cash provided by (used in) financing activities	3,435,000	(620,000)
Effect of exchange rate changes on cash and cash equivalents	(72,000)	(62,000)
Net change in cash and cash equivalents	15,130,000	4,135,000
Cash and cash equivalents, beginning of period	61,637,000	46,041,000
Cash and cash equivalents, end of period	76,767,000	50,176,000
Cash paid during the period for:
Income Taxes	$ 2,303,000	$ 1,105,000