CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES:
Net loss	$ (14,519)	$ (16,308)
Adjustments to reconcile net loss to net cash provided by operating activities:
Stock-based compensation expense	6,103	7,600
Depreciation	9,017	9,445
Amortization of purchased intangibles	3,968	5,045
Amortization of tenant allowance	(125)	0
Deferred income taxes	823	163
Provision for doubtful accounts, net	1,363	1,240
Changes in operating assets and liabilities:
Accounts receivable	(1,719)	(340)
Prepaid expenses and other current assets	(2,248)	(1,627)
Other assets	75	(32)
Accounts payable	(4,352)	(1,404)
Accrued expenses and other current liabilities	(2,954)	(1,690)
Deferred revenue	8,549	12,593
Other liabilities	(463)	1,865
Net cash provided by operating activities	3,518	16,550
INVESTING ACTIVITIES:
Purchases of property and equipment, including capitalized software	(12,176)	(9,251)
Cash held as collateral for foreign exchange forward contracts	2,511	1,443
Payments for acquisitions and intangible assets, net of cash acquired	(345)	(411)
Net cash used in investing activities	(10,010)	(8,219)
FINANCING ACTIVITIES:
Proceeds from issuance of common stock in connection with the exercise of options	7,748	838
Repurchase of common stock	(1,741)	(5,773)
Net cash provided by (used in) financing activities	6,007	(4,935)
EFFECT OF FOREIGN EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	3,957	(794)
CHANGE IN CASH AND CASH EQUIVALENTS	3,472	2,602
CASH AND CASH EQUIVALENTS - Beginning of the period	50,889	48,803
CASH AND CASH EQUIVALENTS - End of the period	54,361	51,405
SUPPLEMENTAL DISCLOSURE OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	540	628
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment recorded in accounts payable	507	53
Leasehold improvements funded by landlord	$ 0	$ 107