Basis of Presentation Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($) source	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of primary revenue sources | source		3
Service provider contract term		1 year
Service provider contract renewal term		1 year
Sales returns period		1 year
Reserve for sales returns, percentage	2.20%	2.30%
Reclassification from tax windfall benefit from stock options		$ (68,444)	$ (642)
Reclassification to deferred income taxes		38,545	11,531
Increase to deferred tax assets (less than)	$ 27,273	27,273		$ 16,752
Increase to accumulated deficit (less than)	(88,997)	(88,997)		(117,909)
Increase to additional paid-in capital (less than)	318,440	$ 318,440		308,697
Software Development
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life		3 years
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscriber contract term		3 years
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Subscriber contract term		5 years
Activation Fees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue	$ 10,700	$ 10,700		11,200
Activation Fees | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Period of revenue recognition		12 months
Activation Fees | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Period of revenue recognition		10 years
Accounting Standards Update 2016-09, Statutory Tax Withholding Component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from tax windfall benefit from stock options			2,700
Reclassification to deferred income taxes			$ 2,700
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to deferred tax assets (less than)				100
Increase to accumulated deficit (less than)				100
Increase to additional paid-in capital (less than)				$ 100
17 Largest Service Providers Agreements | Service Provider Concentration Risk | Revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk percentage		61.00%