Business Combinations (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	12 Months Ended
	Dec. 22, 2014	Dec. 19, 2013	Jan. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Liabilities assumed:
Goodwill				$ 29,201	$ 29,201
Total purchase price allocation
Goodwill				$ 29,201	$ 29,201
Minimum
Additional disclosures
Estimated useful life of intangible assets				1 year
Maximum
Additional disclosures
Estimated useful life of intangible assets				7 years
Developed technology
Additional disclosures
Estimated useful life of intangible assets				1 year 10 months 24 days	2 years 10 months 24 days
Domain names
Additional disclosures
Estimated useful life of intangible assets				2 years 9 months 18 days	3 years 7 months 6 days
Customer relationships
Additional disclosures
Estimated useful life of intangible assets				9 months 18 days	1 year 7 months 6 days
Non-compete agreements
Additional disclosures
Estimated useful life of intangible assets				2 years	3 years
Stock options to purchase common stock
Acquisition
Closing stock price (in dollars per share)				$ 28.71
RSUs
Additional disclosures
Granted to employees (in shares)				2,017,000
Insightera, Ltd.
Acquisition
Cash consideration		$ 9,800
Number of shares issued		427,761
Closing stock price (in dollars per share)		$ 32.89
Number of shares withheld in escrow		137,252
Transaction costs						$ 700
Additional costs of registration of common stock issued						$ 200
Tangible assets:
Cash and cash equivalents		$ 3,624
Accounts receivable		46
Other current assets		60
Property and equipment		71
Other assets		13
Total tangible assets		3,814
Liabilities assumed:
Accounts payable and accrued liabilities		(391)
Deferred revenues		(116)
Other long-term liabilities		(27)
Total liabilities assumed		(534)
Deferred tax liability		374
Intangible assets		4,600
Goodwill		16,404
Total purchase price		23,910
Total purchase price allocation
Intangible assets		4,600
Goodwill		16,404
Insightera, Ltd. | Maximum
Liabilities assumed:
Escrow shares withheld, period						18 months
Insightera, Ltd. | Developed technology
Total purchase price allocation
Intangible assets		$ 3,650
Additional disclosures
Estimated useful life of intangible assets		4 years
Insightera, Ltd. | Domain names
Total purchase price allocation
Intangible assets		$ 250
Additional disclosures
Estimated useful life of intangible assets		3 years
Insightera, Ltd. | Customer relationships
Total purchase price allocation
Intangible assets		$ 700
Additional disclosures
Estimated useful life of intangible assets		3 years
Insightera, Ltd. | RSUs
Additional disclosures
Granted to employees (in shares)			139,464
Value of shares granted to employees			$ 6,100
Immaterial Business Acquisition
Acquisition
Total Consideration	$ 5,000
Cash consideration	$ 200
Number of shares issued	141,074
Closing stock price (in dollars per share)	$ 33.71
Liabilities assumed:
Deferred tax liability	$ 300
Goodwill	3,200
Total purchase price allocation
Net tangible assets acquired	500
Intangible assets	1,600
Goodwill	$ 3,200
Additional disclosures
Estimated useful life of intangible assets	3 years
Immaterial Business Acquisition | RSUs
Liabilities assumed:
Value of shares issued	$ 6,400
Immaterial Business Acquisition | Time based RSU member
Acquisition
Number of shares issued	146,762
Immaterial Business Acquisition | Performance based RSU member
Acquisition
Number of shares issued	42,932