CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Glip, Inc.	Common Stock	Common Stock Glip, Inc.	Additional Paid-in Capital	Additional Paid-in Capital Glip, Inc.	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2014	$ 96,505		$ 7		$ 274,844		$ (251)	$ (178,095)
Beginning Balance, shares at Dec. 31, 2014			68,559
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans	19,413				19,413
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans, shares			3,181
Issuance of shares for business acquisition	3,447				3,447
Issuance of shares of business acquisition, shares			223
Share-based compensation	22,088				22,088
Changes in comprehensive loss	778						778
Net loss	(32,099)							(32,099)
Ending Balance at Dec. 31, 2015	110,132		$ 7		319,792		527	(210,194)
Ending Balance, shares at Dec. 31, 2015			71,963
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans	14,849				14,849
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans, shares			2,374
Issuance of shares for business acquisition		$ 1,080				$ 1,080
Issuance of shares of business acquisition, shares				46
Share-based compensation	31,079				31,079
Changes in comprehensive loss	2,210						2,210
Net loss	(29,309)							(29,309)
Ending Balance at Dec. 31, 2016	130,041		$ 7		366,800		2,737	(239,503)
Ending Balance, shares at Dec. 31, 2016			74,383
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans	21,804		$ 1		21,803
Issuance of common stock in connection with Equity Incentive and Employee Stock Purchase plans, shares			3,594
Issuance of shares for business acquisition		$ 3,560				$ 3,560
Issuance of shares of business acquisition, shares				77
Share-based compensation	42,677				42,677
Changes in comprehensive loss	261						261
Net loss	(26,141)							(26,141)
Ending Balance at Dec. 31, 2017	$ 172,202		$ 8		$ 434,840		$ 2,998	$ (265,644)
Ending Balance, shares at Dec. 31, 2017			78,054