Revenue, Deferred Revenue and Deferred Costs and Other - Deferred Costs and Other (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Change in Contract with Customer, Asset [Abstract]
Balance at beginning of period	$ 21,751	$ 8,469
ASC 606 adoption date impact adjustment	21,751	18,442	$ 33,090	$ 21,751
Additions	17,736	8,607
Revenue recognized	(130)	(245)
Cost of revenue recognized	(5,973)	(2,598)
Sales and marketing expenses recognized	(294)	(254)
Balance at end of period	33,090	18,442
Deferred costs, current			22,595	16,051
Deferred costs, noncurrent			10,495	5,700
Total deferred costs	21,751	18,442	33,090	21,751
Deferred Device Costs
Change in Contract with Customer, Asset [Abstract]
Balance at beginning of period	18,579	8,469
ASC 606 adoption date impact adjustment	29,750	14,366	29,750	18,579
Additions	17,144	8,495
Revenue recognized	0	0
Cost of revenue recognized	(5,973)	(2,598)
Sales and marketing expenses recognized	0	0
Balance at end of period	29,750	14,366
Deferred costs, current			20,961	14,746
Deferred costs, noncurrent			8,789	3,833
Total deferred costs	29,750	14,366	29,750	18,579
Deferred Contract Costs
Change in Contract with Customer, Asset [Abstract]
Balance at beginning of period	2,988	0
ASC 606 adoption date impact adjustment	2,988	3,438	2,868	2,988
Additions	174	0
Revenue recognized	0	0
Cost of revenue recognized	0	0
Sales and marketing expenses recognized	(294)	(254)
Balance at end of period	2,868	3,438
Deferred costs, current			1,162	1,121
Deferred costs, noncurrent			1,706	1,867
Total deferred costs	2,988	3,438	2,868	2,988
Deferred Execution Credits
Change in Contract with Customer, Asset [Abstract]
Balance at beginning of period	184	0
ASC 606 adoption date impact adjustment	184	638	472	184
Additions	418	112
Revenue recognized	(130)	(245)
Cost of revenue recognized	0	0
Sales and marketing expenses recognized	0	0
Balance at end of period	472	638
Deferred costs, current			472	184
Deferred costs, noncurrent			0	0
Total deferred costs	$ 184	$ 638	$ 472	$ 184
Impact of Adoption | ASC 606
Change in Contract with Customer, Asset [Abstract]
ASC 606 adoption date impact adjustment					$ 4,463
Total deferred costs					4,463
Impact of Adoption | ASC 606 | Deferred Device Costs
Change in Contract with Customer, Asset [Abstract]
ASC 606 adoption date impact adjustment					0
Total deferred costs					0
Impact of Adoption | ASC 606 | Deferred Contract Costs
Change in Contract with Customer, Asset [Abstract]
ASC 606 adoption date impact adjustment					3,692
Total deferred costs					3,692
Impact of Adoption | ASC 606 | Deferred Execution Credits
Change in Contract with Customer, Asset [Abstract]
ASC 606 adoption date impact adjustment					771
Total deferred costs					$ 771