CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (12,891)	$ (14,630)	$ (36,461)	$ (33,106)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	944	1,058	2,916	3,354
Stock-based compensation expense	3,670	3,082	10,562	7,876
(Recovery of) provision for doubtful accounts	(92)	222	78	348
Realized gain on sale of available-for-sale securities	0	(7)	(6)	(7)
Amortization (accretion) of premiums and discounts on marketable securities, net	36	32	111	32
Recognition of deferred government grant obligation	(247)	(236)	(910)	(508)
Deferred income tax	5	0	(7)	0
Changes in assets and liabilities:
Accounts receivable	(4,009)	47	(6,734)	(1,448)
Deferred commissions	(135)	(217)	(264)	(104)
Other receivables	(365)	(44)	(447)	(656)
Prepaid expenses and other	415	(218)	(1,098)	(139)
Other assets	(455)	72	(841)	166
Accounts payable	279	857	380	2,276
Deferred revenue	13,228	1,686	15,412	3,528
Accrued expenses and other liabilities	2,410	3,578	(3,012)	1,732
Change in restricted cash	0	0	0	101
Net cash provided by (used in) operating activities	2,793	(4,718)	(20,321)	(16,555)
Cash flows from investing activities
Purchase of property and equipment	(91)	(629)	(1,100)	(1,659)
Purchase of marketable securities	0	(15,692)	(802)	(15,692)
Sale of marketable securities	0	3,012	7,197	3,012
Purchase of intangible assets	(38)	(66)	(152)	(344)
Net cash (used in) provided by investing activities	(129)	(13,375)	5,143	(14,683)
Cash flows from financing activities
Payment of equity issuance costs	0	0	0	(1,346)
Proceeds from option exercises	840	1,062	1,360	1,495
Taxes paid related to net share settlements of stock-based compensation awards	0	0	(761)	0
Changes in restricted cash	0	0	0	300
Repayment of other long-term debt	0	(17)	(18)	(84)
Principal payments on capital lease and financing obligations	(538)	(522)	(1,446)	(1,683)
Distributions to members	0	0	0	(35)
Proceeds from government grants	0	235	183	548
Payments of issuance costs on line of credit	0	0	(33)	0
Net cash provided by (used in) financing activities	302	758	(715)	(805)
Effect of foreign exchange rates on cash	(9)	(3)	(15)	6
Net increase (decrease) in cash and cash equivalents	2,957	(17,338)	(15,908)	(32,037)
Cash and cash equivalents at beginning of period	39,885	86,432	58,750	101,131
Cash and cash equivalents at end of period	42,842	69,094	42,842	69,094
Supplemental cash flow disclosure
Cash paid for interest	600	488	1,392	1,407
Cash paid for income taxes, net of refunds	(26)	0	22	0
Supplemental disclosure of noncash investing and financing activities
Fixed assets acquired through capital lease arrangements	0	0	0	527
Allowance for tenant improvements	80	0	481	698
Accrued distributions to members	0	0	0	60
Purchases of property and equipment, accrued but not paid	$ 505	$ 0	$ 505	$ 0