Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net income	$ 1,297	$ 6,178
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,549	2,584
Stock-based compensation expense	8,737	7,935
Amortization of acquired intangible assets	618	617
Deferred taxes	(3,514)	1,083
Loss on disposal of property and equipment	5	107
Provision for (reversal of) allowance for doubtful accounts	124	(99)
Unrealized loss (gain) on foreign currency forward contract	(6)	(54)
Changes in operating assets and liabilities:
Accounts receivable, net of allowance	(4,921)	(10,486)
Prepaid expenses and other current assets	(1,142)	(1,486)
Accounts payable	1,611	33
Accrued compensation and related benefits	(721)	277
Accrued and other liabilities	(225)	139
Deferred revenues	(682)	3,959
Billings in excess of recognized revenues	200	(1,194)
Other non-current assets	1,331	(7,764)
Net cash provided by operating activities	6,261	1,829
Investing activities:
Payments for business acquisitions, net of cash acquired	(3,841)
Purchases of property and equipment	(6,942)	(8,860)
Net cash used in investing activities	(10,783)	(8,860)
Financing activities:
Proceeds from exercise of stock options	2,304	1,132
Proceeds from employee stock purchase plan	1,866	1,558
Repurchases of common stock	(13,418)	(2,182)
Payments for taxes related to net share settlement of equity awards	(2,439)	(1,161)
Net cash used in financing activities	(11,687)	(653)
Effect of exchange rate changes on cash and cash equivalents	172	60
Net change in cash and cash equivalents	(16,037)	(7,624)
Cash and cash equivalents, beginning of period	116,787	126,158
Cash and cash equivalents, end of period	100,750	118,534
Supplemental disclosure of cash flow information:
Taxes	1,876	2,616
Property and equipment received and accrued in accounts payable and accrued and other liabilities	$ 1,533	$ 913