Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Investment owned at cost	$ 8,100		$ 8,100
Ownership interest of investment owned	5.00%		5.00%
Warranty period offered			4 years
Warranty reserve	$ 25,668	$ 17,823	$ 25,668	$ 17,823	$ 23,169		$ 22,075	$ 16,761	$ 16,724
Income tax expense	61	(2,075)	(56)	$ (1,977)
Reduction to accumulated deficit	(651,197)		(651,197)				(659,210)
Convertible senior notes, net - long-term	280,599		$ 280,599				202,984
Cumulative Effect, Period of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Income tax expense		$ 13
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2020-06
Summary Of Significant Accounting Policies [Line Items]
Reduction to accumulated deficit						$ 9,000
Additional paid in capital						(85,800)
Convertible senior notes, net - long-term						$ 76,800
Complementary products
Summary Of Significant Accounting Policies [Line Items]
Warranty period offered			4 years
Tandem Pump
Summary Of Significant Accounting Policies [Line Items]
Warranty period offered			4 years
Slim cartridges and infusion sets
Summary Of Significant Accounting Policies [Line Items]
Warranty period offered			6 months
Technology-Based Intangible Assets
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			5 years
Convertible senior notes | Level 2 | Convertible debt
Summary Of Significant Accounting Policies [Line Items]
Convertible senior notes, fair value	$ 326,600		$ 326,600				$ 333,500