Business Combinations - Additional Information (Details) - USD ($) $ in Millions			12 Months Ended
	Oct. 13, 2015	Mar. 21, 2014	Dec. 31, 2016
Business Acquisition [Line Items]
RSUs issued pursuant to retention plan, in connection with the acquisition (in shares)			4,216,000
Vesting period			4 years
RSUs vested (in shares)			2,894,000
We Are Cloud, Inc
Business Acquisition [Line Items]
Percent of outstanding shares acquired	100.00%
Business acquisition, fair value of consideration transferred, cash	$ 46.4
Cash portion of fair value consideration transferred	$ 7.0
Number of months consideration held in escrow, to be released	12 months
Business acquisition, transaction costs incurred	$ 1.0
We Are Cloud, Inc | Restricted Stock Units
Business Acquisition [Line Items]
RSUs issued pursuant to retention plan, in connection with the acquisition (in shares)	500,000
Vesting period	3 years
We Are Cloud, Inc | Developed technology
Business Acquisition [Line Items]
Acquired intangible assets, useful lives	4 years 6 months
We Are Cloud, Inc | Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets, useful lives	4 years 6 months
We Are Cloud, Inc | Maximum
Business Acquisition [Line Items]
Number of months consideration were held in escrow	18 months
Zopim
Business Acquisition [Line Items]
Business acquisition, fair value of consideration transferred, cash		$ 4.9
Consideration transferred		15.8
Consideration transferred, common stock		10.9
Cash to be paid pursuant to retention plan		$ 3.0	$ 3.0
Zopim | Restricted Stock Units
Business Acquisition [Line Items]
RSUs issued pursuant to retention plan, in connection with the acquisition (in shares)		0.9
RSUs vested (in shares)			600,000