CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net loss	$ (12,045)	$ (7,447)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	997	1,169
Stock-based compensation expense	3,390	2,174
Provision for doubtful accounts	122	74
Realized gain on sale of available-for-sale securities	(2)	0
Amortization (accretion) of premiums and discounts on marketable securities, net	39	0
Recognition of deferred government grant obligation	(433)	(66)
Changes in assets and liabilities:
Accounts receivable	(881)	(911)
Deferred commissions	(12)	145
Other receivables	(224)	(188)
Prepaid expenses and other	(186)	144
Other assets	(63)	56
Accounts payable	(696)	157
Deferred revenue	(3,215)	(672)
Accrued expenses and other liabilities	(5,869)	(3,892)
Change in restricted cash	0	28
Net cash used in operating activities	(19,078)	(9,229)
Cash flows from investing activities
Purchase of property and equipment	(412)	(871)
Sale of marketable securities	4,793	0
Purchase of intangible assets	(55)	(83)
Net cash provided by (used in) investing activities	4,326	(954)
Cash flows from financing activities
Payment of equity issuance costs	0	(1,073)
Proceeds from option exercises	284	80
Taxes paid related to net share settlements of stock-based compensation awards	(761)	0
Changes in restricted cash	0	300
Repayment of other long-term debt	0	(25)
Principal payments on capital lease and financing obligations	(432)	(678)
Proceeds from government grants	183	313
Net cash used in financing activities	(726)	(1,083)
Effect of foreign exchange rates on cash	(46)	28
Net decrease in cash and cash equivalents	(15,524)	(11,238)
Cash and cash equivalents at beginning of period	58,750	101,131
Cash and cash equivalents at end of period	43,226	89,893
Supplemental cash flow disclosure
Cash paid for interest	322	423
Cash paid for income taxes, net of refunds	8	0
Supplemental disclosure of noncash investing and financing activities
Fixed assets acquired through capital lease arrangements	0	184
Allowance for tenant improvements	186	698
Accrued distributions to members	0	60
Purchases of property and equipment, accrued but not paid	$ 65	$ 0