Insulet (PODD) 10-Q 6 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 25, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-33462
Entity Registrant Name	INSULET CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3523891
Entity Address, Address Line One	100 Nagog Park
Entity Address, City or Town	Acton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01720
City Area Code	978
Local Phone Number	600-7000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.001 Par Value Per Share
Trading Symbol	PODD
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding (in shares)		61,821,566
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001145197
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 419,882	$ 113,906
Short-term investments	185,622	175,040
Accounts receivable trade, less allowance for doubtful accounts of $4,174 and $3,610	65,052	63,294
Unbilled receivable	12,485	13,378
Inventories	90,207	71,414
Prepaid expenses and other current assets	20,653	24,254
Total current assets	793,901	461,286
Long-term investments	31,006	140,784
Property, plant and equipment, net	355,865	258,379
Other intangible assets, net	12,834	10,383
Goodwill	39,713	39,646
Other assets	35,071	18,266
Total assets	1,268,390	928,744
Current Liabilities
Accounts payable	21,245	25,500
Accrued expenses and other current liabilities	92,037	90,157
Total current liabilities	113,282	115,657
Convertible debt, net	985,771	591,978
Other liabilities	18,769	9,010
Total liabilities	1,117,822	716,645
Commitments and contingencies (Note 10)
Stockholders’ Equity
Preferred stock, $.001 par value, 5,000,000 authorized; none issued and outstanding	0	0
Common stock, $.001 par value, 100,000,000 authorized; 61,786,969 and 59,188,758 issued and outstanding	62	59
Additional paid-in capital	832,140	898,559
Accumulated deficit	(676,982)	(683,614)
Accumulated other comprehensive loss	(4,652)	(2,905)
Total stockholders’ equity	150,568	212,099
Total liabilities and stockholders’ equity	$ 1,268,390	$ 928,744

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4,174	$ 3,610
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	61,786,969	59,188,758
Common stock, outstanding (in shares)	61,786,969	59,188,758

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 192,115	$ 151,076	$ 528,806	$ 398,916
Cost of revenue	69,035	49,107	182,612	139,060
Gross profit	123,080	101,969	346,194	259,856
Operating expenses:
Research and development	30,779	22,336	94,997	61,404
Sales and marketing	47,749	35,952	136,766	105,576
General and administrative	27,548	36,816	82,559	81,686
Total operating expenses	106,076	95,104	314,322	248,666
Operating income	17,004	6,865	31,872	11,190
Interest expense, net of portion capitalized	(9,370)	(6,846)	(23,627)	(22,044)
Loss on extinguishment of debt	(6,451)	0	(6,451)	(10)
Other (expense) income, net	(53)	1,834	5,924	5,202
Income (loss) before income taxes	1,130	1,853	7,718	(5,662)
Income tax expense	(278)	(194)	(1,086)	(939)
Net income (loss)	$ 852	$ 1,659	$ 6,632	$ (6,601)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.01	$ 0.03	$ 0.11	$ (0.11)
Diluted (in dollars per share)	$ 0.01	$ 0.03	$ 0.11	$ (0.11)
Weighted-average number of shares used in calculating net income (loss) per share:
Basic (in shares)	60,743,211	59,016,863	59,986,163	58,779,672
Diluted (in shares)	62,335,679	61,146,466	61,728,018	58,779,672

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 852	$ 1,659	$ 6,632	$ (6,601)
Other comprehensive loss, net of tax
Foreign currency translation adjustment, net of tax	(1,858)	4	(3,032)	(1,055)
Unrealized gain (loss) on available-for-sale debt securities, net of tax	35	(70)	1,285	(904)
Total other comprehensive loss, net of tax	(1,823)	(66)	(1,747)	(1,959)
Total comprehensive (loss) income	$ (971)	$ 1,593	$ 4,885	$ (8,560)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	0.375% Convertible Senior Notes	1.25% Convertible Senior Notes	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital0.375% Convertible Senior Notes	Additional Paid-in Capital1.25% Convertible Senior Notes	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2017				58,319,348
Beginning balance at Dec. 31, 2017	$ 158,516			$ 58	$ 866,206			$ (707,255)	$ (493)
Exercise of options to purchase common stock (in shares)				375,154
Exercise of options to purchase common stock	12,000				12,000
Issuance of shares for employee stock purchase plan (in shares)				24,643
Issuance of shares for employee stock purchase plan	1,481				1,481
Stock-based compensation expense	31,205				31,205
Restricted stock units vested, net of shares withheld for taxes (in shares)				349,441
Restricted stock units vested, net of shares withheld for taxes	(13,845)			$ 1	(13,846)
Conversion feature, net of issuance costs	(3,217)				(3,217)
Net income (loss)	(6,601)							(6,601)
Other comprehensive income (loss)	(1,959)								(1,959)
Ending balance (in shares) at Sep. 30, 2018				59,068,586
Ending balance at Sep. 30, 2018	197,929			$ 59	893,829			(693,507)	(2,452)
Beginning balance (in shares) at Jun. 30, 2018				58,975,395
Beginning balance at Jun. 30, 2018	179,148			$ 59	876,641			(695,166)	(2,386)
Exercise of options to purchase common stock (in shares)				66,785
Exercise of options to purchase common stock	2,264				2,264
Stock-based compensation expense	16,088				16,088
Restricted stock units vested, net of shares withheld for taxes (in shares)				26,406
Restricted stock units vested, net of shares withheld for taxes	(1,159)				(1,159)
Conversion feature, net of issuance costs			$ (5)				$ (5)
Net income (loss)	1,659							1,659
Other comprehensive income (loss)	(66)								(66)
Ending balance (in shares) at Sep. 30, 2018				59,068,586
Ending balance at Sep. 30, 2018	$ 197,929			$ 59	893,829			(693,507)	(2,452)
Beginning balance (in shares) at Dec. 31, 2018	59,188,758			59,188,758
Beginning balance at Dec. 31, 2018	$ 212,099			$ 59	898,559			(683,614)	(2,905)
Exercise of options to purchase common stock (in shares)	1,192,397			1,188,043
Exercise of options to purchase common stock	$ 40,917			$ 2	40,915
Issuance of shares for employee stock purchase plan (in shares)				27,613
Issuance of shares for employee stock purchase plan	2,030				2,030
Stock-based compensation expense	20,704				20,704
Restricted stock units vested, net of shares withheld for taxes (in shares)				225,063
Restricted stock units vested, net of shares withheld for taxes	(8,234)				(8,234)
Conversion feature, net of issuance costs		$ 207,768	(438,642)			$ 207,768	(438,642)
Issuance of shares for debt repayment (in shares)				1,157,492
Issuance of shares for debt repayment	194,401			$ 1	194,400
Purchase of capped call options	(85,360)				(85,360)
Net income (loss)	6,632							6,632
Other comprehensive income (loss)	$ (1,747)								(1,747)
Ending balance (in shares) at Sep. 30, 2019	61,786,969			61,786,969
Ending balance at Sep. 30, 2019	$ 150,568			$ 62	832,140			(676,982)	(4,652)
Beginning balance (in shares) at Jun. 30, 2019				60,149,926
Beginning balance at Jun. 30, 2019	249,780			$ 60	930,383			(677,834)	(2,829)
Exercise of options to purchase common stock (in shares)				471,356
Exercise of options to purchase common stock	17,257			$ 1	17,256
Stock-based compensation expense	6,626				6,626
Restricted stock units vested, net of shares withheld for taxes (in shares)				8,195
Restricted stock units vested, net of shares withheld for taxes	(291)				(291)
Conversion feature, net of issuance costs		$ 207,768	$ (438,642)			$ 207,768	$ (438,642)
Issuance of shares for debt repayment (in shares)				1,157,492
Issuance of shares for debt repayment	194,401			$ 1	194,400
Purchase of capped call options	(85,360)				(85,360)
Net income (loss)	852							852
Other comprehensive income (loss)	$ (1,823)								(1,823)
Ending balance (in shares) at Sep. 30, 2019	61,786,969			61,786,969
Ending balance at Sep. 30, 2019	$ 150,568			$ 62	$ 832,140			$ (676,982)	$ (4,652)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical)	Sep. 30, 2019	Dec. 31, 2018
0.375% Convertible Senior Notes
Debt, interest rate	0.375%	0.375%
1.25% Convertible Senior Notes
Debt, interest rate	1.25%

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net income (loss)	$ 6,632	$ (6,601)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	18,784	11,254
Non-cash interest expense	24,274	21,790
Stock-based compensation expense	20,704	31,205
Loss on extinguishment of debt	6,451	10
Provision for bad debts	2,644	2,588
Other	1,850	(245)
Changes in operating assets and liabilities:
Accounts receivable and unbilled receivable	(5,957)	(24,581)
Inventories	(20,046)	(25,279)
Prepaid expenses and other assets	(4,883)	(5,258)
Accounts payable, accrued expenses and other current liabilities	(2,550)	2,938
Deferred revenue	847	(2,761)
Other liabilities	2,717	400
Net cash provided by operating activities	51,467	5,460
Cash flows from investing activities
Capital expenditures	(114,585)	(124,855)
Acquisition of intangible assets	(6,390)	(2,704)
Purchases of investments	(63,904)	(145,575)
Receipts from the maturity or sale of investments	165,275	129,415
Net cash used in investing activities	(19,604)	(143,719)
Cash flows from financing activities
Proceeds from issuance of convertible notes, net of issuance costs	780,202	0
Repayment of convertible debt	(453,608)	(6,699)
Purchase of capped call options	(85,360)	0
Proceeds from exercise of stock options and issuance of common stock under employee stock purchase plan	42,945	13,464
Payments for taxes related to net share settlement of equity awards	(8,234)	(13,846)
Net cash provided by (used in) financing activities	275,945	(7,081)
Effect of exchange rate changes on cash	(1,832)	(674)
Net increase (decrease) in cash, cash equivalents and restricted cash	305,976	(146,014)
Cash, cash equivalents and restricted cash at beginning of period	113,906	272,577
Cash, cash equivalents and restricted cash at end of period	419,882	126,563
Supplemental cash flow information:
Purchases of property and equipment included in accounts payable and accrued expenses	10,616	$ 10,711
Additions to ROU assets resulting from new operating lease liabilities	$ 5,117

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	Nature of the Business Insulet Corporation (“Insulet”) is primarily engaged in the development, manufacturing and sale of its proprietary Omnipod ® System, an innovative, discreet and easy-to-use continuous insulin delivery system for people with insulin-dependent diabetes. The Omnipod System consists of two product lines: the Omnipod Insulin Management System (“Omnipod”), which Insulet has been selling since 2005, and its next generation Omnipod DASH TM Insulin Management System (“Omnipod DASH” or “DASH”). Insulet began a full market release of Omnipod DASH in the United States at the end of the first quarter of 2019. Collectively, these products are referred to as the “Omnipod System”. In addition to using the Omnipod System for insulin delivery, Insulet also partners with global pharmaceutical and biotechnology companies to tailor the Omnipod System technology platform for the delivery of their drugs across other therapeutic areas. The majority of Insulet's drug delivery revenue currently consists of sales to Amgen supplying the Neulasta ® Onpro ®

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Basis of Presentation The accompanying financial statements reflect the consolidated operations of Insulet and its subsidiaries (the “Company”). The unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions in the application of certain of its significant accounting policies that may materially affect the reported amounts of assets, liabilities, equity, revenue and expenses. Actual results may differ from those estimates. In management's opinion, the unaudited consolidated financial statements contain all normal recurring adjustments necessary for a fair statement of the interim results reported. Operating results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results that may be expected for the full year ending December 31, 2019 , or for any other subsequent interim period. The year-end balance sheet data was derived from audited consolidated financial statements. These consolidated financial statements do not include all of the annual disclosures required by U.S. GAAP; accordingly, they should be read in conjunction with the Company’s audited consolidated financial statements contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . Shipping and Handling Costs Shipping and handling costs are included in general and administrative expenses and were $2.2 million for both the three months ended September 30, 2019 and 2018 and were $7.1 million and $4.6 million for the nine months ended September 30, 2019 and 2018 , respectively. Reclassification of Prior Period Amounts Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation. Software license costs have been reallocated from general and administrative expenses to research and development and sales and marketing expenses based on license usage. These reclassifications have no effect on previously reported net income. Recently Adopted Accounting Standards Effective January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 and its related amendments (collectively referred to as ASC 842), which amends the guidance in former ASC Topic 840, Leases. The new standard requires lessees to recognize right-of-use (“ROU”) assets and lease liabilities on the balance sheet for those leases classified as operating leases. The Company adopted ASC 842 on January 1, 2019 using the modified retrospective method, whereby the new guidance is applied prospectively as of the date of adoption and prior periods are not restated. The Company elected the practical expedients that permit the Company to not reassess (1) whether any expired or existing contracts are or contain leases, (2) the lease classification for any expired or existing leases, and (3) any initial direct costs for any existing leases as of the effective date. The Company also excludes leases with an expected term of less than one year from the application of ASC 842. Upon the adoption, the Company recorded ROU assets of $8.8 million and operating lease liabilities of $10.8 million on its consolidated balance sheet. The difference between the approximate value of the ROU assets and the approximate value of the lease obligations was primarily attributable to a former cease-use liability. See Note 11 for additional information regarding leases. Effective January 1, 2019, the Company early adopted ASU 2018-15, Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). ASU 2018-15 requires certain costs to implement a cloud computing arrangement that is a service contract to be capitalized consistent with the rules applicable to internal-use software capitalization projects. The Company adopted this new guidance effective January 1, 2019, prospectively. The Company defers eligible costs related to the implementation of cloud computing arrangements within other current and non-current assets and amortizes such costs over the expected term of the hosting arrangement to the same income statement line as the associated cloud operating expenses. Adoption of this standard resulted in the Company capitalizing $0.4 million and $2.4 million of cloud computing implementation costs for the three and nine months ended September 30, 2019 , respectively.

Revenue and Contract Acquisitio

Revenue and Contract Acquisition Costs	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue and Contract Acquisition Costs	Revenue and Contract Acquisition Costs The following table summarizes revenue from contracts with customers for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 U.S. Omnipod $ 109,464 $ 81,970 $ 293,641 $ 230,289 International Omnipod 67,753 50,214 187,377 117,127 Total Diabetes Revenue 177,217 132,184 481,018 347,416 Drug Delivery 14,898 18,892 47,788 51,500 Total $ 192,115 $ 151,076 $ 528,806 $ 398,916 Revenue for customers comprising more than 10% of total revenue were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Amgen, Inc. * 12% * 13% Ypsomed * * * 11% Cardinal Health Inc. and affiliates 11% 12% 11% 12% * Represents less than 10% of consolidated revenue. Deferred revenue related to unsatisfied performance obligations was included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Accrued expenses and other current liabilities $ 2,007 $ 1,184 Other liabilities 1,011 931 Total deferred revenue $ 3,018 $ 2,115 Revenue recognized during the three and nine months ended September 30, 2019 included in deferred revenue at the beginning of 2019 was $0.1 million and $1.1 million , respectively. Revenue recognized during the three and nine months ended September 30, 2018 included in deferred revenue at the beginning of 2018 was $ 0.6 million and $2.5 million , respectively. No revenue was recognized during the three and nine months ended September 30, 2019 and 2018 from performance obligations satisfied or partially satisfied in previous periods. Contract acquisition costs, representing capitalized commission costs related to new customers, net of amortization, were included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Prepaid expenses and other current assets $ 9,006 $ 7,277 Other assets 19,282 15,988 Total capitalized contract acquisition costs, net $ 28,288 $ 23,265 The Company recognized $2.3 million and $6.4 million of amortization of capitalized contract acquisition costs during the three and nine months ended September 30, 2019 , respectively. The Company recognized $1.8 million and $5.0 million of amortization of capitalized contract acquisition costs during the three and nine months ended September 30, 2018 , respectively.

Investments

Investments	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Cash and Cash Equivalents Included in the Company's cash and cash equivalents are restricted cash amounts set aside for collateral on outstanding letters of credit totaling $2.7 million at both September 30, 2019 and December 31, 2018 . Marketable Securities The Company's short-term and long-term investments in debt securities had maturity dates that range from 4 days to 23 months as of September 30, 2019 . The Company’s investment portfolio included approximately 14 available-for-sale debt securities that had insignificant unrealized loss positions as of September 30, 2019 and December 31, 2018 . The Company's investments had insignificant realized gains or losses for both the three and nine months ended September 30, 2019 and 2018 . The Company uses the following fair value hierarchy to measure the fair value of assets and liabilities: Level 1 — quoted prices in active markets for identical assets or liabilities; Level 2 — observable inputs other than quoted prices in active markets for identical assets or liabilities; Level 3 — unobservable inputs for which there is little or no market data, which require the Company to develop its own assumptions. The Company had no Level 3 assets or liabilities as of September 30, 2019 and December 31, 2018 . The following table provides amortized cost, gross unrealized gains and losses, fair value and the level in the fair value hierarchy for the Company's investments as of September 30, 2019 and December 31, 2018 : (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value Level 1 Level 2 September 30, 2019 Money market mutual funds $ 83,342 $ — $ — $ 83,342 $ 83,342 $ — U.S. government and agency bonds 4,995 — — 4,995 4,995 — Total cash equivalents $ 88,337 $ — $ — $ 88,337 $ 88,337 $ — U.S. government and agency bonds $ 106,135 $ 204 $ (7 ) $ 106,332 $ 94,764 $ 11,568 Corporate bonds 71,329 156 (1 ) 71,484 — 71,484 Certificates of deposit 7,779 27 — 7,806 — 7,806 Total short-term investments $ 185,243 $ 387 $ (8 ) $ 185,622 $ 94,764 $ 90,858 U.S. government and agency bonds $ 27,873 $ 125 $ (20 ) $ 27,978 $ 9,979 $ 17,999 Corporate bonds 814 44 (38 ) 820 — 820 Certificates of deposit 2,190 18 — 2,208 — 2,208 Total long-term investments $ 30,877 $ 187 $ (58 ) $ 31,006 $ 9,979 $ 21,027 December 31, 2018 Money market mutual funds $ 47,199 $ — $ — $ 47,199 $ 47,199 $ — Total cash equivalents $ 47,199 $ — $ — $ 47,199 $ 47,199 $ — U.S. government and agency bonds $ 112,995 $ — $ (486 ) $ 112,509 $ 69,605 $ 42,904 Corporate bonds 56,235 — (210 ) 56,025 — 56,025 Certificates of deposit 6,506 — — 6,506 — 6,506 Total short-term investments $ 175,736 $ — $ (696 ) $ 175,040 $ 69,605 $ 105,435 U.S. government and agency bonds $ 90,458 $ 99 $ (155 ) $ 90,402 $ 64,086 $ 26,316 Corporate bonds 46,743 43 (68 ) 46,718 — 46,718 Certificates of deposit 3,664 — — 3,664 — 3,664 Total long-term investments $ 140,865 $ 142 $ (223 ) $ 140,784 $ 64,086 $ 76,698

Convertible Debt, Net

Convertible Debt, Net	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Convertible Debt, Net	Convertible Debt, Net The Company had outstanding convertible debt and related debt issuance costs on its consolidated balance sheet as follows: As of (in thousands) September 30, 2019 December 31, 2018 1.25% Convertible Senior Notes, due September 2021 $ 119,988 $ 344,992 1.375% Convertible Senior Notes, due November 2024 402,500 402,500 0.375% Convertible Senior Notes, due September 2026 $ 800,000 $ — Unamortized debt discount (315,017 ) (143,616 ) Debt issuance costs (21,700 ) (11,898 ) Total convertible debt, net $ 985,771 $ 591,978 The carrying amount and the estimated fair value of the Company's convertible debt, which is based on the Level 2 quoted market prices as of September 30, 2019 and December 31, 2018 were as follows: As of September 30, 2019 December 31, 2018 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value 1.25% Convertible Senior Notes, due September 2021 $ 108,666 $ 335,968 $ 301,006 $ 483,851 1.375% Convertible Senior Notes, due November 2024 302,796 512,797 290,972 426,026 0.375% Convertible Senior Notes, due September 1, 2026 574,309 812,928 — — Total $ 985,771 $ 1,661,693 $ 591,978 $ 909,877 0.375% Convertible Senior Notes In September 2019, the Company issued $800.0 million aggregate principal amount of 0.375% Convertible Senior Notes due September 2026 (the “ 0.375% Notes”). The interest rate on the notes is 0.375% per annum, payable semi-annually in arrears in cash in March and September of each year. The 0.375% Notes are convertible into the Company's common stock at an initial conversion rate of 4.4105 shares of common stock per $1,000 principal amount of the 0.375% Notes, which is equivalent to a conversion price of approximately $226.73 per share, subject to adjustment under certain circumstances. The 0.375% Notes will be convertible prior to the close of business on the business day immediately preceding June 1, 2026 only under certain circumstances and during certain periods, and will be convertible on or after June 1, 2026 until the close of business on the second scheduled trading day immediately preceding the maturity date (September 1, 2026). The Company recorded a debt discount of $213.0 million related to the 0.375% Notes resulting from the allocation of a portion of the proceeds to the fair value of the conversion feature reflecting a nonconvertible debt borrowing rate of 5.29% per annum. This debt discount was recorded as additional paid-in capital and is being amortized as non-cash interest expense over the seven -year term of the 0.375% Notes. The Company also incurred debt issuance costs and other expenses related to the 0.375% Notes of approximately $19.8 million , of which $5.3 million was reclassified as a reduction to the value of the conversion feature allocated to equity. The remaining $14.5 million of debt issuance costs is presented as a reduction of debt in the consolidated balance sheet and is being amortized using the effective interest method as non-cash interest expense over the seven year term of the 0.375% Notes. The net proceeds of $780.2 million were used to fund the redemption of the Company's 1.25% Convertible Senior Notes due September 2021 and for the purchase of capped call options (“Capped Calls”), both of which are discussed below. The 0.375% Notes contain provisions that allow for additional interest to holders of the notes upon failure to timely file documents or reports that the Company is required to file with the Securities and Exchange Commission. The additional interest is at a rate of 0.5% per annum of the principal amounts of the notes outstanding for a period of 360 days . If the Company merges or consolidates with a foreign entity, then additional taxes may be required to be paid by the Company under the terms of the 0.375% Notes. The Company determined that the higher interest payments required and tax payments required in certain circumstances are considered embedded derivatives and should be bifurcated and accounted for at fair value. The Company assesses the value of the embedded derivatives at each balance sheet date. The derivatives had nominal value at the balance sheet date. In conjunction with the issuance of the Convertible Senior Notes, the Company paid $85.4 million to enter into Capped Calls on the Company’s common stock with certain counterparties, which was recorded as a reduction to additional paid-in capital on the consolidated balance sheet. By entering into the Capped Calls, the Company expects to reduce the potential dilution to its common stock (or, in the event the conversion is settled in cash, to provide a source of cash to settle a portion of its cash payment obligation) in the event that at the time of conversion its stock price exceeds the conversion price under the Convertible Senior Notes. The Capped Calls have an initial strike price of $335.90 per share, which represents a premium of 100% over the last reported sale price of the Company’s common stock of $167.95 per share on the date of the transaction (September 3, 2019). The Capped Calls cover 3.5 million shares of common stock. 1.25% Convertible Senior Notes During the three months ended September 30, 2019 , the Company repurchased $225.0 million in principal of 1.25% Convertible Senior Notes due September 2021 ( $202.9 million net of discount and issuance costs) for total consideration of $648.0 million . The total consideration was comprised of $453.6 million in cash and $ 194.4 million representing the fair value of the 1.16 million shares issued. The Company allocated $438.6 million of the settlement to the fair value of the equity component and $209.4 million to the debt component, which resulted in a $6.5 million loss on extinguishment for both the three and nine months ended September 30, 2019 . In October 2019, the Company repurchased the remaining $120.0 million in principal of 1.25% Convertible Senior Notes due September 2021 ( $108.3 million net of discount and issuance costs) for total consideration of $315.0 million . The total consideration was comprised of $210.0 million in cash and $105.0 million representing the fair value of the 0.7 million shares issued. The Company allocated $203.7 million of the settlement to the fair value of the equity component and $111.4 million to the debt component, which resulted in a $3.1 million loss on extinguishment, which will be recorded during the fourth quarter of 2019.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2019
Disclosure Potential Common Shares Excluded From Computation Of Diluted Net Loss Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share Basic net income (loss) per share is computed by dividing net income (loss) by the weighted average number of common shares outstanding for the period, excluding unvested restricted common shares. Diluted net income (loss) per share is computed using the weighted average number of common shares outstanding and, when dilutive, potential common share equivalents from outstanding stock options and restricted stock units (using the treasury-stock method), and potential common shares from the Company's convertible debt (using the if-converted method). The table below sets forth the components used in the computation of basic and diluted net income (loss) per share for the three and nine months ended September 30, 2019 and 2018. Because the Company reported a net loss for the nine months ended September 30, 2018 , all potential dilutive common shares have been excluded from the computation of the diluted net loss per share for the nine months ended September 30, 2018 , as the effect would have been anti-dilutive. Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except share and per share data) 2019 2018 2019 2018 Numerator: Net income (loss) $ 852 $ 1,659 $ 6,632 $ (6,601 ) Denominator: Basic weighted average common shares outstanding 60,743,211 59,016,863 59,986,163 58,779,672 Effect of dilutive securities Stock options 1,370,792 1,719,796 1,514,245 — Restricted stock units 221,676 409,807 227,610 — Convertible debt — — — — Diluted shares 62,335,679 61,146,466 61,728,018 58,779,672 Net income (loss) per share: Basic $ 0.01 $ 0.03 $ 0.11 $ (0.11 ) Diluted $ 0.01 $ 0.03 $ 0.11 $ (0.11 ) For the three and nine months ended September 30, 2019 , certain potential outstanding shares from stock options, restricted stock units and convertible debt were excluded from the computation of diluted net income per share because the effect of including these items was anti-dilutive. Additionally, certain performance-based restricted stock units were excluded from the computation of diluted net income per share because the underlying performance conditions for such restricted stock units had not yet been met. The number of potential common share equivalents excluded from the computation of diluted net income (loss) per share for the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 1.25% Convertible Senior Notes 2,055,786 5,910,954 2,055,786 5,910,954 1.375% Convertible Senior Notes 4,319,429 4,319,429 4,319,429 4,319,429 0.375% Convertible Senior Notes 3,528,400 — 3,528,400 — Unvested restricted stock units 455,876 300,438 455,824 865,206 Stock options 7,858 223,183 136,342 3,117,326 Total 10,367,349 10,754,004 10,495,781 14,212,915

Inventories

Inventories	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories At the end of each period, inventories were comprised of the following: As of (in thousands) September 30, 2019 December 31, 2018 Raw materials $ 18,605 $ 10,347 Work-in-process 40,962 30,222 Finished goods 30,640 30,845 Total inventories $ 90,207 $ 71,414

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets, Net	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets, Net	Goodwill and Other Intangible Assets, Net The changes in the carrying amounts of goodwill for the nine months ended September 30, 2019 were as follows: (in thousands) Goodwill at December 31, 2018 $ 39,646 Foreign currency translation 67 Goodwill at September 30, 2019 $ 39,713 The gross carrying amount, accumulated amortization and net book value of intangible assets at the end of each period were as follows: As of September 30, 2019 December 31, 2018 (in thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer and contractual relationships $ 9,827 $ (2,543 ) $ 7,284 $ 6,109 $ (1,880 ) $ 4,229 Internal-use software 11,103 (6,370 ) 4,733 11,262 (5,108 ) 6,154 Intellectual property 840 (23 ) 817 — — — Total $ 21,770 $ (8,936 ) $ 12,834 $ 17,371 $ (6,988 ) $ 10,383 Amortization expense for intangible assets was $0.7 million and $0.5 million for the three months ended September 30, 2019 and 2018 , respectively. Amortization expense for intangible assets was $1.9 million and $1.3 million for the nine months ended September 30, 2019 and 2018 , respectively. Estimated future amortization expense by year is as follows: Years Ending December 31, (in thousands) 2019 (remaining) $ 769 2020 2,641 2021 2,155 2022 1,562 2023 1,100 Thereafter 4,607 Total $ 12,834

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2019
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities The components of accrued expenses and other current liabilities were as follows: As of (in thousands) September 30, 2019 December 31, 2018 Employee compensation and related costs $ 43,024 $ 37,822 Professional and consulting services 14,325 14,925 Accrued rebates 5,866 2,796 Supplier purchases 3,123 7,742 Other 25,699 26,872 Accrued expenses and other current liabilities $ 92,037 $ 90,157 Product Warranty Costs The Company provides a four -year warranty on Personal Diabetes Managers (“PDMs”) sold in the United States and Europe and a five -year warranty on PDMs sold in Canada and may replace Pods that do not function in accordance with product specifications. The Company estimates its warranty at the time the product is shipped based on historical experience and the estimated cost to service the claims. Since the Company continues to introduce new products and versions, the anticipated performance of the product over the warranty period is also considered in estimating warranty reserves. Warranty expense is recorded in cost of goods sold in the consolidated statements of operations. Cost to service the claims reflects the current product cost. A reconciliation of the changes in the Company’s product warranty liability is as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Product warranty liability at beginning of period $ 6,639 $ 5,503 $ 6,379 $ 5,337 Warranty expense 3,271 1,763 8,637 5,264 Warranty claims settled (3,122 ) (1,548 ) (8,228 ) (4,883 ) Product warranty liability at end of period $ 6,788 $ 5,718 $ 6,788 $ 5,718 Product warranty liability was included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Accrued expenses and other current liabilities $ 3,019 $ 2,701 Other liabilities 3,769 3,678 Total $ 6,788 $ 6,379

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings Between May 5, 2015 and June 16, 2015, three class action lawsuits were filed by shareholders in the U.S. District Court, for the District of Massachusetts, against the Company and certain individual and former executives of the Company. Two suits subsequently were voluntarily dismissed. Arkansas Teacher Retirement System v. Insulet, et al., 1:15-cv-12345, (“ATRS”) alleged that the Company (and certain executives) committed violations of Sections 10(b) and 20(a) and Rule 10b-5 of the Securities Exchange Act of 1934 by making allegedly false and misleading statements about the Company’s business, operations, and prospects. On February 8, 2018, the parties executed a binding stipulation of settlement, under which all claims were released and a payment was made into an escrow account for the plaintiffs and the class they purport to represent. On August 6, 2018, the Court issued an order approving the settlement. The Company had previously accrued fees and expenses in connection with this matter for the amount of the final settlement liability that was not covered by insurance, the amount of which was not material to the Company's consolidated financial statements. In addition, on April 26, 2017, a derivative action (Walker v. DeSisto, et al., 1:17-cv-10738) (“Walker”) was filed, and on October 13, 2017, a second derivative action (Carnazza v. DeSisto, et al., 1:17-cv-11977) (“Carnazza”) was filed, both on behalf of the Company, each by a shareholder in the U.S. District Court for the District of Massachusetts against the Company (as a nominal defendant) and certain individual current and former officers and directors of the Company. The allegations in the actions are substantially similar to those alleged in the securities class action. The actions seek, among other things, damages, disgorgement of certain types of compensation or profits, and attorneys’ fees and costs. On July 11, 2018, the parties executed a binding stipulation of settlement, under which all claims were released and a payment of attorneys’ fees and reimbursement of expenses will be paid to plaintiffs’ counsel, subject to the Court’s approval. On July 13, 2018, the plaintiffs filed a motion for preliminary approval of the settlement, which is pending. The Company expects that such fees and expenses payable to plaintiff's counsel will be covered by the Company's insurance. The Company is, from time to time, involved in the normal course of business in various legal proceedings, including intellectual property, contract, employment and product liability suits. Although the Company is unable to quantify the exact financial impact of any of these matters, the Company believes that none of these currently pending matters will have an outcome material to its financial condition or business. Fees To Former European Distributor Following the expiration of an agreement with a former European distributor on June 30, 2018, the Company was required to pay a quarterly per-unit fee for Omnipod sales to certain customers of the former European distributor for a one-year period through June 30, 2019. The Company recognized a liability and an associated intangible asset for this fee as qualifying sales occurred. The methodology applicable for determining the total fee under the distribution agreement is subject to an active arbitration proceeding in Switzerland. The final amount of the fee could vary significantly depending on the number of customers who count for purposes of calculating the fee under the terms of the agreement. The Company estimates that the final aggregate fee is in the range of $5 million to $55 million . As of September 30, 2019 the Company had recognized $7.8 million

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases As discussed in Note 2, ASC 842 requires lessees to recognize ROU assets and lease liabilities on the balance sheet based on the present value of the future minimum lease payments over the lease term at commencement date. As the Company's leases do not provide an implicit rate, the Company uses an incremental borrowing rate based on the information available at lease commencement in determining the present value of lease payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. As of September 30, 2019 , the Company leased certain office spaces, laboratory space, warehouse space and automobiles, all of which were classified as operating leases. Certain of the Company's operating leases include escalating rental payments. Some leases include the option to extend for up to 5 years , and some include options to terminate the leases at certain times within the lease term. As of September 30, 2019 , the Company included options to extend that are reasonably certain to be exercised in the operating lease assets and liabilities. The Company's total operating lease cost, which is recorded in general and administrative expenses in the consolidated statements of operations, was $1.2 million and $3.0 million for the three and nine months ended September 30, 2019 , respectively. For the three and nine months ended September 30, 2018 , total rental expense was $0.9 million and $2.6 million , respectively. Cash paid for amounts included in the measurement of lease liabilities was $1.0 million and $2.6 million for three and nine months ended September 30, 2019 , respectively. The future minimum undiscounted lease payments under operating leases as of September 30, 2019 are as follows: Years Ending December 31, (in thousands) 2019 (remaining) $ 984 2020 3,628 2021 4,118 2022 3,658 2023 1,278 Thereafter 2,216 Total future minimum lease payments 15,882 Less: imputed interest (1,991 ) Present value of future minimum lease payments $ 13,891 As of September 30, 2019 , ROU assets and operating lease liabilities were included in the following consolidated balance sheet accounts in the amounts shown: As of September 30, 2019 (in thousands) ROU asset: Other assets $ 12,190 Operating lease liabilities: Accrued expenses and other current liabilities $ 2,341 Other liabilities 11,550 Total $ 13,891 As of September 30, 2019 , the weighted average remaining lease term for operating leases was 4.1 years and the weighted-average discount rate used to determine the operating lease liability was 6.2% .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The following table reflects the Company's stock-based compensation expense related to share-based awards for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, Unamortized Expense Weighted Average Remaining Expense Period (Years) ($ in thousands) 2019 2018 2019 2018 At September 30, 2019 Stock options $ 1,469 $ 3,957 $ 4,691 $ 8,587 $ 9,225 2.5 Restricted stock units 4,714 11,835 14,851 21,734 35,926 2.0 Employee stock purchase plan 443 296 1,162 884 295 0.2 Total $ 6,626 $ 16,088 $ 20,704 $ 31,205 $ 45,446 The following summarizes stock option activity for the nine months ended September 30, 2019 : Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Term (Years) Outstanding at December 31, 2018 3,077,624 $ 39.16 Granted 125,640 93.16 Exercised (1,192,397 ) 34.68 $ 99,206 Forfeited / Expired (124,198 ) 50.58 Outstanding at September 30, 2019 1,886,669 $ 44.84 $ 226,571 5.6 Vested, September 30, 2019 1,447,398 $ 38.25 $ 183,351 4.8 Vested or expected to vest, September 30, 2019 (1) 1,835,967 $ 222,101 (1) Represents total outstanding stock options as of September 30, 2019 , adjusted for estimated forfeitures. The following table summarizes activity for the Company’s restricted stock units during the nine months ended September 30, 2019 : Number of Shares Weighted Average Fair Value Outstanding at December 31, 2018 752,207 $ 55.02 Granted 317,212 94.68 Vested (317,481 ) 45.29 Forfeited (69,013 ) 67.34 Outstanding at September 30, 2019 682,925 $ 76.72

Interest Expense

Interest Expense	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Interest Expense	Interest Expense Interest expense, net of portion capitalized was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Contractual coupon interest $ 2,553 $ 2,440 $ 7,477 $ 7,382 Accretion of debt discount 8,202 6,712 22,202 19,840 Amortization of debt issuance costs 700 661 2,072 1,950 Capitalized interest (2,085 ) (2,967 ) (8,124 ) (7,128 ) Interest expense, net of portion capitalized $ 9,370 $ 6,846 $ 23,627 $ 22,044 Interest expense related to convertible debt for the three and nine months ended September 30, 2019 was as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (in thousands) 1.375% 1.25% 0.375% Total 1.375% 1.25% 0.375% Total Contractual coupon interest $ 1,384 $ 961 $ 208 $ 2,553 $ 4,152 $ 3,117 $ 208 $ 7,477 Amortization of debt discount and issuance costs 4,021 3,006 1,875 8,902 11,824 10,575 1,875 24,274 Total $ 5,405 $ 3,967 $ 2,083 $ 11,455 $ 15,976 $ 13,692 $ 2,083 $ 31,751 Interest expense related to convertible debt for the three and nine months ended September 30, 2018 is as follows: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands) 1.375% 1.25% Total 1.375% 1.25% 2.0% Total Contractual coupon interest $ 1,362 $ 1,078 $ 2,440 $ 4,129 $ 3,234 $ 19 $ 7,382 Amortization of debt discount and issuance costs 3,746 3,627 7,373 11,001 10,729 60 21,790 Total $ 5,108 $ 4,705 $ 9,813 $ 15,130 $ 13,963 $ 79 $ 29,172

Income Tax Expense

Income Tax Expense	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Tax Expense	Income Tax Expense The Company's effective tax rate for the three and nine months ended September 30, 2019 was 24.6% and 14.1% , compared with 10.5% and 16.6% for the same periods of 2018. Income tax benefits have not been recorded for losses in jurisdictions where valuation allowances exist against net deferred tax assets; primarily in the United States. As of September 30, 2019 and December 31, 2018 , the Company maintained a full valuation allowance against its U.S. net deferred tax assets based on the determination that it is not more likely than not these future benefits will be realized before expiration.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements reflect the consolidated operations of Insulet and its subsidiaries (the “Company”). The unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions in the application of certain of its significant accounting policies that may materially affect the reported amounts of assets, liabilities, equity, revenue and expenses. Actual results may differ from those estimates. In management's opinion, the unaudited consolidated financial statements contain all normal recurring adjustments necessary for a fair statement of the interim results reported. Operating results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results that may be expected for the full year ending December 31, 2019 , or for any other subsequent interim period. The year-end balance sheet data was derived from audited consolidated financial statements. These consolidated financial statements do not include all of the annual disclosures required by U.S. GAAP; accordingly, they should be read in conjunction with the Company’s audited consolidated financial statements contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 .
Reclassification of Prior Period Amounts	Reclassification of Prior Period Amounts
Recently Adopted and Not Yet Adopted Accounting Pronouncements	Recently Adopted Accounting Standards Effective January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 and its related amendments (collectively referred to as ASC 842), which amends the guidance in former ASC Topic 840, Leases. The new standard requires lessees to recognize right-of-use (“ROU”) assets and lease liabilities on the balance sheet for those leases classified as operating leases. The Company adopted ASC 842 on January 1, 2019 using the modified retrospective method, whereby the new guidance is applied prospectively as of the date of adoption and prior periods are not restated. The Company elected the practical expedients that permit the Company to not reassess (1) whether any expired or existing contracts are or contain leases, (2) the lease classification for any expired or existing leases, and (3) any initial direct costs for any existing leases as of the effective date. The Company also excludes leases with an expected term of less than one year from the application of ASC 842. Upon the adoption, the Company recorded ROU assets of $8.8 million and operating lease liabilities of $10.8 million on its consolidated balance sheet. The difference between the approximate value of the ROU assets and the approximate value of the lease obligations was primarily attributable to a former cease-use liability. See Note 11 for additional information regarding leases. Effective January 1, 2019, the Company early adopted ASU 2018-15, Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). ASU 2018-15 requires certain costs to implement a cloud computing arrangement that is a service contract to be capitalized consistent with the rules applicable to internal-use software capitalization projects. The Company adopted this new guidance effective January 1, 2019, prospectively. The Company defers eligible costs related to the implementation of cloud computing arrangements within other current and non-current assets and amortizes such costs over the expected term of the hosting arrangement to the same income statement line as the associated cloud operating expenses. Adoption of this standard resulted in the Company capitalizing $0.4 million and $2.4 million of cloud computing implementation costs for the three and nine months ended September 30, 2019 , respectively.
Product Warranty Costs	Product Warranty Costs The Company provides a four -year warranty on Personal Diabetes Managers (“PDMs”) sold in the United States and Europe and a five

Revenue and Contract Acquisit_2

Revenue and Contract Acquisition Costs (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Summary of Revenue from Contracts with Customers	The following table summarizes revenue from contracts with customers for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 U.S. Omnipod $ 109,464 $ 81,970 $ 293,641 $ 230,289 International Omnipod 67,753 50,214 187,377 117,127 Total Diabetes Revenue 177,217 132,184 481,018 347,416 Drug Delivery 14,898 18,892 47,788 51,500 Total $ 192,115 $ 151,076 $ 528,806 $ 398,916
Schedule of Revenue from Major Customers	Revenue for customers comprising more than 10% of total revenue were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Amgen, Inc. * 12% * 13% Ypsomed * * * 11% Cardinal Health Inc. and affiliates 11% 12% 11% 12% * Represents less than 10% of consolidated revenue.
Summary of Deferred Revenue	Deferred revenue related to unsatisfied performance obligations was included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Accrued expenses and other current liabilities $ 2,007 $ 1,184 Other liabilities 1,011 931 Total deferred revenue $ 3,018 $ 2,115
Summary of Contract Acquisition Costs	Contract acquisition costs, representing capitalized commission costs related to new customers, net of amortization, were included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Prepaid expenses and other current assets $ 9,006 $ 7,277 Other assets 19,282 15,988 Total capitalized contract acquisition costs, net $ 28,288 $ 23,265

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost, Gross Unrealized Gains and Losses, Fair Value and Level in Fair Value Hierarchy for Investments	The following table provides amortized cost, gross unrealized gains and losses, fair value and the level in the fair value hierarchy for the Company's investments as of September 30, 2019 and December 31, 2018 : (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value Level 1 Level 2 September 30, 2019 Money market mutual funds $ 83,342 $ — $ — $ 83,342 $ 83,342 $ — U.S. government and agency bonds 4,995 — — 4,995 4,995 — Total cash equivalents $ 88,337 $ — $ — $ 88,337 $ 88,337 $ — U.S. government and agency bonds $ 106,135 $ 204 $ (7 ) $ 106,332 $ 94,764 $ 11,568 Corporate bonds 71,329 156 (1 ) 71,484 — 71,484 Certificates of deposit 7,779 27 — 7,806 — 7,806 Total short-term investments $ 185,243 $ 387 $ (8 ) $ 185,622 $ 94,764 $ 90,858 U.S. government and agency bonds $ 27,873 $ 125 $ (20 ) $ 27,978 $ 9,979 $ 17,999 Corporate bonds 814 44 (38 ) 820 — 820 Certificates of deposit 2,190 18 — 2,208 — 2,208 Total long-term investments $ 30,877 $ 187 $ (58 ) $ 31,006 $ 9,979 $ 21,027 December 31, 2018 Money market mutual funds $ 47,199 $ — $ — $ 47,199 $ 47,199 $ — Total cash equivalents $ 47,199 $ — $ — $ 47,199 $ 47,199 $ — U.S. government and agency bonds $ 112,995 $ — $ (486 ) $ 112,509 $ 69,605 $ 42,904 Corporate bonds 56,235 — (210 ) 56,025 — 56,025 Certificates of deposit 6,506 — — 6,506 — 6,506 Total short-term investments $ 175,736 $ — $ (696 ) $ 175,040 $ 69,605 $ 105,435 U.S. government and agency bonds $ 90,458 $ 99 $ (155 ) $ 90,402 $ 64,086 $ 26,316 Corporate bonds 46,743 43 (68 ) 46,718 — 46,718 Certificates of deposit 3,664 — — 3,664 — 3,664 Total long-term investments $ 140,865 $ 142 $ (223 ) $ 140,784 $ 64,086 $ 76,698

Convertible Debt, Net (Tables)

Convertible Debt, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Outstanding Convertible Debt and Related Debt Issuance Costs	The Company had outstanding convertible debt and related debt issuance costs on its consolidated balance sheet as follows: As of (in thousands) September 30, 2019 December 31, 2018 1.25% Convertible Senior Notes, due September 2021 $ 119,988 $ 344,992 1.375% Convertible Senior Notes, due November 2024 402,500 402,500 0.375% Convertible Senior Notes, due September 2026 $ 800,000 $ — Unamortized debt discount (315,017 ) (143,616 ) Debt issuance costs (21,700 ) (11,898 ) Total convertible debt, net $ 985,771 $ 591,978
Summary of Carrying Amount and Estimated Fair Value of Convertible Debt	The carrying amount and the estimated fair value of the Company's convertible debt, which is based on the Level 2 quoted market prices as of September 30, 2019 and December 31, 2018 were as follows: As of September 30, 2019 December 31, 2018 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value 1.25% Convertible Senior Notes, due September 2021 $ 108,666 $ 335,968 $ 301,006 $ 483,851 1.375% Convertible Senior Notes, due November 2024 302,796 512,797 290,972 426,026 0.375% Convertible Senior Notes, due September 1, 2026 574,309 812,928 — — Total $ 985,771 $ 1,661,693 $ 591,978 $ 909,877

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure Potential Common Shares Excluded From Computation Of Diluted Net Loss Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) per Share	The table below sets forth the components used in the computation of basic and diluted net income (loss) per share for the three and nine months ended September 30, 2019 and 2018. Because the Company reported a net loss for the nine months ended September 30, 2018 , all potential dilutive common shares have been excluded from the computation of the diluted net loss per share for the nine months ended September 30, 2018 , as the effect would have been anti-dilutive. Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except share and per share data) 2019 2018 2019 2018 Numerator: Net income (loss) $ 852 $ 1,659 $ 6,632 $ (6,601 ) Denominator: Basic weighted average common shares outstanding 60,743,211 59,016,863 59,986,163 58,779,672 Effect of dilutive securities Stock options 1,370,792 1,719,796 1,514,245 — Restricted stock units 221,676 409,807 227,610 — Convertible debt — — — — Diluted shares 62,335,679 61,146,466 61,728,018 58,779,672 Net income (loss) per share: Basic $ 0.01 $ 0.03 $ 0.11 $ (0.11 ) Diluted $ 0.01 $ 0.03 $ 0.11 $ (0.11 )
Potential Common Share Equivalents Excluded from Computation of Diluted Net Income (Loss) per Share	The number of potential common share equivalents excluded from the computation of diluted net income (loss) per share for the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 1.25% Convertible Senior Notes 2,055,786 5,910,954 2,055,786 5,910,954 1.375% Convertible Senior Notes 4,319,429 4,319,429 4,319,429 4,319,429 0.375% Convertible Senior Notes 3,528,400 — 3,528,400 — Unvested restricted stock units 455,876 300,438 455,824 865,206 Stock options 7,858 223,183 136,342 3,117,326 Total 10,367,349 10,754,004 10,495,781 14,212,915

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Components of Inventories	At the end of each period, inventories were comprised of the following: As of (in thousands) September 30, 2019 December 31, 2018 Raw materials $ 18,605 $ 10,347 Work-in-process 40,962 30,222 Finished goods 30,640 30,845 Total inventories $ 90,207 $ 71,414

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Changes in Carrying Amounts of Goodwill	The changes in the carrying amounts of goodwill for the nine months ended September 30, 2019 were as follows: (in thousands) Goodwill at December 31, 2018 $ 39,646 Foreign currency translation 67 Goodwill at September 30, 2019 $ 39,713
Components of Other Intangible Assets	The gross carrying amount, accumulated amortization and net book value of intangible assets at the end of each period were as follows: As of September 30, 2019 December 31, 2018 (in thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer and contractual relationships $ 9,827 $ (2,543 ) $ 7,284 $ 6,109 $ (1,880 ) $ 4,229 Internal-use software 11,103 (6,370 ) 4,733 11,262 (5,108 ) 6,154 Intellectual property 840 (23 ) 817 — — — Total $ 21,770 $ (8,936 ) $ 12,834 $ 17,371 $ (6,988 ) $ 10,383
Amortization Expense Expected for Next Five Years	Estimated future amortization expense by year is as follows: Years Ending December 31, (in thousands) 2019 (remaining) $ 769 2020 2,641 2021 2,155 2022 1,562 2023 1,100 Thereafter 4,607 Total $ 12,834

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Payables and Accruals [Abstract]
Components of Accrued Expenses and Other Current Liabilities	The components of accrued expenses and other current liabilities were as follows: As of (in thousands) September 30, 2019 December 31, 2018 Employee compensation and related costs $ 43,024 $ 37,822 Professional and consulting services 14,325 14,925 Accrued rebates 5,866 2,796 Supplier purchases 3,123 7,742 Other 25,699 26,872 Accrued expenses and other current liabilities $ 92,037 $ 90,157
Reconciliation of Changes in Product Warranty Liability	A reconciliation of the changes in the Company’s product warranty liability is as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Product warranty liability at beginning of period $ 6,639 $ 5,503 $ 6,379 $ 5,337 Warranty expense 3,271 1,763 8,637 5,264 Warranty claims settled (3,122 ) (1,548 ) (8,228 ) (4,883 ) Product warranty liability at end of period $ 6,788 $ 5,718 $ 6,788 $ 5,718 Product warranty liability was included in the following consolidated balance sheet accounts in the amounts shown: As of (in thousands) September 30, 2019 December 31, 2018 Accrued expenses and other current liabilities $ 3,019 $ 2,701 Other liabilities 3,769 3,678 Total $ 6,788 $ 6,379

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Future Minimum Undiscounted Lease Payments	The future minimum undiscounted lease payments under operating leases as of September 30, 2019 are as follows: Years Ending December 31, (in thousands) 2019 (remaining) $ 984 2020 3,628 2021 4,118 2022 3,658 2023 1,278 Thereafter 2,216 Total future minimum lease payments 15,882 Less: imputed interest (1,991 ) Present value of future minimum lease payments $ 13,891
Summary of ROU Assets and Operating Lease Liabilities	As of September 30, 2019 , ROU assets and operating lease liabilities were included in the following consolidated balance sheet accounts in the amounts shown: As of September 30, 2019 (in thousands) ROU asset: Other assets $ 12,190 Operating lease liabilities: Accrued expenses and other current liabilities $ 2,341 Other liabilities 11,550 Total $ 13,891

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expense and Stock Option Activity	The following table reflects the Company's stock-based compensation expense related to share-based awards for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, Unamortized Expense Weighted Average Remaining Expense Period (Years) ($ in thousands) 2019 2018 2019 2018 At September 30, 2019 Stock options $ 1,469 $ 3,957 $ 4,691 $ 8,587 $ 9,225 2.5 Restricted stock units 4,714 11,835 14,851 21,734 35,926 2.0 Employee stock purchase plan 443 296 1,162 884 295 0.2 Total $ 6,626 $ 16,088 $ 20,704 $ 31,205 $ 45,446 The following summarizes stock option activity for the nine months ended September 30, 2019 : Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Term (Years) Outstanding at December 31, 2018 3,077,624 $ 39.16 Granted 125,640 93.16 Exercised (1,192,397 ) 34.68 $ 99,206 Forfeited / Expired (124,198 ) 50.58 Outstanding at September 30, 2019 1,886,669 $ 44.84 $ 226,571 5.6 Vested, September 30, 2019 1,447,398 $ 38.25 $ 183,351 4.8 Vested or expected to vest, September 30, 2019 (1) 1,835,967 $ 222,101 (1) Represents total outstanding stock options as of September 30, 2019 , adjusted for estimated forfeitures.
Summary of Restricted Stock Units Activity	The following table summarizes activity for the Company’s restricted stock units during the nine months ended September 30, 2019 : Number of Shares Weighted Average Fair Value Outstanding at December 31, 2018 752,207 $ 55.02 Granted 317,212 94.68 Vested (317,481 ) 45.29 Forfeited (69,013 ) 67.34 Outstanding at September 30, 2019 682,925 $ 76.72

Interest Expense (Tables)

Interest Expense (Tables)	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Interest and Other Expense	Interest expense, net of portion capitalized was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Contractual coupon interest $ 2,553 $ 2,440 $ 7,477 $ 7,382 Accretion of debt discount 8,202 6,712 22,202 19,840 Amortization of debt issuance costs 700 661 2,072 1,950 Capitalized interest (2,085 ) (2,967 ) (8,124 ) (7,128 ) Interest expense, net of portion capitalized $ 9,370 $ 6,846 $ 23,627 $ 22,044 Interest expense related to convertible debt for the three and nine months ended September 30, 2019 was as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (in thousands) 1.375% 1.25% 0.375% Total 1.375% 1.25% 0.375% Total Contractual coupon interest $ 1,384 $ 961 $ 208 $ 2,553 $ 4,152 $ 3,117 $ 208 $ 7,477 Amortization of debt discount and issuance costs 4,021 3,006 1,875 8,902 11,824 10,575 1,875 24,274 Total $ 5,405 $ 3,967 $ 2,083 $ 11,455 $ 15,976 $ 13,692 $ 2,083 $ 31,751 Interest expense related to convertible debt for the three and nine months ended September 30, 2018 is as follows: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands) 1.375% 1.25% Total 1.375% 1.25% 2.0% Total Contractual coupon interest $ 1,362 $ 1,078 $ 2,440 $ 4,129 $ 3,234 $ 19 $ 7,382 Amortization of debt discount and issuance costs 3,746 3,627 7,373 11,001 10,729 60 21,790 Total $ 5,108 $ 4,705 $ 9,813 $ 15,130 $ 13,963 $ 79 $ 29,172

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
Significant Accounting Policies [Line Items]
Other assets	$ 12,190		$ 12,190
Operating lease liability	13,891		13,891
Cost of revenue	69,035	$ 49,107	182,612	$ 139,060
Shipping and Handling
Significant Accounting Policies [Line Items]
Cost of revenue	2,200	$ 2,200	7,100	$ 4,600
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Other assets					$ 8,800
Operating lease liability					$ 10,800
Accounting Standards Update 2018-15
Significant Accounting Policies [Line Items]
Capitalizing of cloud computing implementation costs	$ 400		$ 2,400

Revenue and Contract Acquisit_3

Revenue and Contract Acquisition Costs - Summary of Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 192,115	$ 151,076	$ 528,806	$ 398,916
U.S. Omnipod
Disaggregation of Revenue [Line Items]
Revenue	109,464	81,970	293,641	230,289
International Omnipod
Disaggregation of Revenue [Line Items]
Revenue	67,753	50,214	187,377	117,127
Diabetes
Disaggregation of Revenue [Line Items]
Revenue	177,217	132,184	481,018	347,416
Drug Delivery
Disaggregation of Revenue [Line Items]
Revenue	$ 14,898	$ 18,892	$ 47,788	$ 51,500

Revenue and Contract Acquisit_4

Revenue and Contract Acquisition Costs - Schedule of Revenue from Major Customers - Concentration Risk (Details) - Customer Concentration Risk - Sales Revenue	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Amgen, Inc.
Significant Accounting Policies [Line Items]
Total revenue, percentage		12.00%		13.00%
Ypsomed
Significant Accounting Policies [Line Items]
Total revenue, percentage				11.00%
Cardinal Health Inc. and affiliates
Significant Accounting Policies [Line Items]
Total revenue, percentage	11.00%	12.00%	11.00%	12.00%

Revenue and Contract Acquisit_5

Revenue and Contract Acquisition Costs - Summary of Deferred Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Accrued expenses and other current liabilities	$ 2,007	$ 1,184
Other liabilities	1,011	931
Total deferred revenue	$ 3,018	$ 2,115

Revenue and Contract Acquisit_6

Revenue and Contract Acquisition Costs - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue recognized	$ 100,000	$ 600,000	$ 1,100,000	$ 2,500,000
Revenue recognized from performance obligations satisfied in previous periods	0	0	0	0
Amortization of capitalized commission costs	$ 2,300,000	$ (1,800,000)	$ (6,400,000)	$ (5,000,000)

Revenue and Contract Acquisit_7

Revenue and Contract Acquisition Costs - Summary of Contract Acquisition Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Prepaid expenses and other current assets	$ 9,006	$ 7,277
Other assets	19,282	15,988
Total capitalized contract acquisition costs, net	$ 28,288	$ 23,265

Investments - Narrative (Detail

Investments - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)security	Dec. 31, 2018USD ($)security
Debt Securities, Available-for-sale [Line Items]
Restricted cash and cash equivalents | $	$ 2.7	$ 2.7
Number of positions | security	14	14
Minimum
Debt Securities, Available-for-sale [Line Items]
Derivative maturity date range	4 days
Maximum
Debt Securities, Available-for-sale [Line Items]
Derivative maturity date range	23 months

Investments - Summary of Amorti

Investments - Summary of Amortized Cost, Gross Unrealized Gains and Losses, Fair Value and Level in Fair Value Hierarchy for Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 88,337	$ 47,199
Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	88,337	47,199
Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	185,243	175,736
Gross Unrealized Gains	387	0
Gross Unrealized (Losses)	(8)	(696)
Short-term investments | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	185,622	175,040
Short-term investments | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	94,764	69,605
Short-term investments | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	90,858	105,435
Short-term investments | U.S. government and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	106,135	112,995
Gross Unrealized Gains	204	0
Gross Unrealized (Losses)	(7)	(486)
Short-term investments | U.S. government and agency bonds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	106,332	112,509
Short-term investments | U.S. government and agency bonds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	94,764	69,605
Short-term investments | U.S. government and agency bonds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	11,568	42,904
Short-term investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	71,329	56,235
Gross Unrealized Gains	156	0
Gross Unrealized (Losses)	(1)	(210)
Short-term investments | Corporate bonds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	71,484	56,025
Short-term investments | Corporate bonds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Short-term investments | Corporate bonds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	71,484	56,025
Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	7,779	6,506
Gross Unrealized Gains	27	0
Gross Unrealized (Losses)	0	0
Short-term investments | Certificates of deposit | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	7,806	6,506
Short-term investments | Certificates of deposit | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Short-term investments | Certificates of deposit | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	7,806	6,506
Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	30,877	140,865
Gross Unrealized Gains	187	142
Gross Unrealized (Losses)	(58)	(223)
Long-term investments | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	31,006	140,784
Long-term investments | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	9,979	64,086
Long-term investments | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	21,027	76,698
Long-term investments | U.S. government and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	27,873	90,458
Gross Unrealized Gains	125	99
Gross Unrealized (Losses)	(20)	(155)
Long-term investments | U.S. government and agency bonds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	27,978	90,402
Long-term investments | U.S. government and agency bonds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	9,979	64,086
Long-term investments | U.S. government and agency bonds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	17,999	26,316
Long-term investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	814	46,743
Gross Unrealized Gains	44	43
Gross Unrealized (Losses)	(38)	(68)
Long-term investments | Corporate bonds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	820	46,718
Long-term investments | Corporate bonds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Long-term investments | Corporate bonds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	820	46,718
Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	2,190	3,664
Gross Unrealized Gains	18	0
Gross Unrealized (Losses)	0	0
Long-term investments | Certificates of deposit | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,208	3,664
Long-term investments | Certificates of deposit | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Long-term investments | Certificates of deposit | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,208	3,664
Money market mutual funds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	83,342	47,199
Money market mutual funds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	83,342	47,199
Money market mutual funds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	$ 0
U.S. government and agency bonds | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	4,995
U.S. government and agency bonds | Level 1 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	4,995
U.S. government and agency bonds | Level 2 | Recurring fair value measurements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0

Convertible Debt, Net - Outstan

Convertible Debt, Net - Outstanding Convertible Debt and Related Debt Issuance Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Unamortized debt discount	$ (315,017)	$ (143,616)
Debt issuance costs	(21,700)	(11,898)
Total convertible debt, net	$ 985,771	$ 591,978
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	1.25%	1.25%	1.25%
1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	1.375%	1.375%	1.375%
0.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	0.375%	0.375%
Convertible Debt | 1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of Senior Notes	$ 119,988	$ 344,992
Convertible Debt | 1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of Senior Notes	402,500	402,500
Convertible Debt | 0.375% Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of Senior Notes	$ 800,000	$ 0

Convertible Debt, Net - Narrati

Convertible Debt, Net - Narrative (Details) $ / shares in Units, shares in Thousands	1 Months Ended		3 Months Ended			9 Months Ended
	Oct. 31, 2019USD ($)shares	Sep. 30, 2019USD ($)$ / shares$ / optionshares	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)$ / shares$ / optionshares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)$ / shares$ / option	Sep. 30, 2018USD ($)	Sep. 03, 2019$ / shares	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Unamortized discount		$ 315,017,000		$ 315,017,000		$ 315,017,000			$ 143,616,000
Repurchased amount						453,608,000	$ 6,699,000
Loss on extinguishment of debt				$ 6,451,000	$ 0	$ 6,451,000	$ 10,000
0.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate		0.375%		0.375%		0.375%			0.375%
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate		1.25%		1.25%		1.25%
Senior Notes | 0.375% Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount of senior notes		$ 800,000,000		$ 800,000,000		$ 800,000,000
Debt, interest rate		0.375%		0.375%		0.375%
Proceeds from issuance of convertible notes, net of issuance costs						$ 780,200,000
Debt conversion rate		0.0044105
Conversion price (in dollars per share) | $ / shares		$ 226.73		$ 226.73		$ 226.73
Unamortized discount		$ 213,000,000		$ 213,000,000		$ 213,000,000
Nonconvertible debt borrowing rate		5.29%		5.29%		5.29%
Debt discount amortization period		7 years
Deferred financing costs, gross		$ 19,800,000		$ 19,800,000		$ 19,800,000
Finance costs reclassified against equity		5,300,000
Debt issuance costs		14,500,000		$ 14,500,000		$ 14,500,000
Price at which capped call options entered		$ 85,400,000
Stock price (in dollars per share) | $ / shares								$ 167.95
Number of capped shares (in shares) | shares		3,500
Senior Notes | 0.375% Convertible Senior Notes | Price Risk Derivative
Debt Instrument [Line Items]
Cap price (in dollars per share) | $ / option		335.90		335.90		335.90
Sale price premium (as a percentage)		100.00%		100.00%		100.00%
Senior Notes | 0.375% Convertible Senior Notes | Upto 360 Days
Debt Instrument [Line Items]
Debt instrument, additional interest in event of reporting violation		0.50%
Debt instrument, redemption period		360 days
Senior Notes | 1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate		1.25%		1.25%		1.25%
Total consideration		$ 648,000,000		$ 648,000,000		$ 648,000,000
Repurchased amount				453,600,000
Repurchased face amount		225,000,000		225,000,000		225,000,000
Repurchase amount		202,900,000		202,900,000		202,900,000
Debt fair value				$ 194,400,000
Shares issued | shares				1,160
Carrying amount of equity component		438,600,000		$ 438,600,000		438,600,000
Convertible debt		$ 209,400,000		209,400,000		209,400,000
Loss on extinguishment of debt				$ 6,500,000		$ 6,500,000
Senior Notes | 1.25% Convertible Senior Notes | Subsequent event
Debt Instrument [Line Items]
Total consideration	$ 315,000,000
Repurchased amount	210,000,000
Repurchased face amount	120,000,000
Repurchase amount	108,300,000
Debt fair value	$ 105,000,000
Shares issued | shares	700
Carrying amount of equity component			$ 203,700,000
Convertible debt			111,400,000
Loss on extinguishment of debt			$ 3,100,000

Convertible Debt, Net - Summary

Convertible Debt, Net - Summary of Carrying Amount and Estimated Fair Value of Convertible Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
1.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	1.25%
1.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	1.375%	1.375%	1.375%
0.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	0.375%	0.375%
Level 2 | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	$ 985,771	$ 591,978
Level 2 | Carrying Value | 1.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	108,666	301,006
Level 2 | Carrying Value | 1.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	302,796	290,972
Level 2 | Carrying Value | 0.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	574,309	0
Level 2 | Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	1,661,693	909,877
Level 2 | Estimated Fair Value | 1.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	335,968	483,851
Level 2 | Estimated Fair Value | 1.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	512,797	426,026
Level 2 | Estimated Fair Value | 0.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument value	$ 812,928	$ 0

Net Income (Loss) Per Share - C

Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income (loss)	$ 852	$ 1,659	$ 6,632	$ (6,601)
Denominator:
Basic weighted average common shares outstanding (in shares)	60,743,211	59,016,863	59,986,163	58,779,672
Effect of dilutive securities
Diluted shares (in shares)	62,335,679	61,146,466	61,728,018	58,779,672
Net income (loss) per share:
Basic (in dollars per share)	$ 0.01	$ 0.03	$ 0.11	$ (0.11)
Diluted (in dollars per share)	$ 0.01	$ 0.03	$ 0.11	$ (0.11)
Stock options
Effect of dilutive securities
Effect of dilutive securities (in shares)	1,370,792	1,719,796	1,514,245	0
Restricted stock units
Effect of dilutive securities
Effect of dilutive securities (in shares)	221,676	409,807	227,610	0
Convertible debt
Effect of dilutive securities
Effect of dilutive securities (in shares)	0	0	0	0

Net Income (Loss) Per Share - P

Net Income (Loss) Per Share - Potential Common Share Equivalents Excluded from Computation of Diluted Net Income (Loss) per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	10,367,349	10,754,004	10,495,781	14,212,915
1.25% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	2,055,786	5,910,954	2,055,786	5,910,954
1.375% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	4,319,429	4,319,429	4,319,429	4,319,429
0.375% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	3,528,400	0	3,528,400	0
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	455,876	300,438	455,824	865,206
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total dilutive common shares (in shares)	7,858	223,183	136,342	3,117,326
1.25% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, interest rate	1.25%	1.25%	1.25%	1.25%	1.25%
1.375% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, interest rate	1.375%	1.375%	1.375%	1.375%	1.375%
0.375% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, interest rate	0.375%		0.375%		0.375%

Inventories - Components of Inv

Inventories - Components of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 18,605	$ 10,347
Work-in-process	40,962	30,222
Finished goods	30,640	30,845
Total inventories	$ 90,207	$ 71,414

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets, Net - Summary of Changes in Carrying Amounts of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Goodwill [Roll Forward]
Goodwill at December 31, 2018	$ 39,646
Foreign currency translation	67
Goodwill at September 30, 2019	$ 39,713

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets, Net - Components of Other Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 21,770	$ 17,371
Accumulated Amortization	(8,936)	(6,988)
Net Book Value	12,834	10,383
Customer and contractual relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	9,827	6,109
Accumulated Amortization	(2,543)	(1,880)
Net Book Value	7,284	4,229
Internal-use software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	11,103	11,262
Accumulated Amortization	(6,370)	(5,108)
Net Book Value	4,733	6,154
Intellectual property
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	840	0
Accumulated Amortization	(23)	0
Net Book Value	$ 817	$ 0

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets, Net - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of other intangible assets	$ 0.7	$ 0.5	$ 1.9	$ 1.3

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets, Net - Amortization Expense Expected for Next Five Years (Details) $ in Thousands	Sep. 30, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2019 (remaining)	$ 769
2020	2,641
2021	2,155
2022	1,562
2023	1,100
Thereafter	4,607
Net Book Value	$ 12,834

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Employee compensation and related costs	$ 43,024	$ 37,822
Professional and consulting services	14,325	14,925
Accrued rebates	5,866	2,796
Supplier purchases	3,123	7,742
Other	25,699	26,872
Accrued expenses and other current liabilities	$ 92,037	$ 90,157

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Narrative (Details)	9 Months Ended
	Sep. 30, 2019
United States
Product Warranty Liability [Line Items]
Product warranty term for PDMs	4 years
CANADA
Product Warranty Liability [Line Items]
Product warranty term for PDMs	5 years

Accrued Expenses and Other Cu_5

Accrued Expenses and Other Current Liabilities - Product Warranty Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Product warranty liability at beginning of period	$ 6,639	$ 5,503	$ 6,379	$ 5,337
Warranty expense	3,271	1,763	8,637	5,264
Warranty claims settled	(3,122)	(1,548)	(8,228)	(4,883)
Product warranty liability at end of period	6,788	5,718	6,788	5,718
Composition of balance:
Accrued expenses and other current liabilities					$ 3,019	$ 2,701
Other liabilities					3,769	3,678
Total warranty balance	$ 6,639	$ 5,503	$ 6,788	$ 5,337	$ 6,788	$ 6,379

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details)	1 Months Ended
	Jun. 16, 2015lawsuit	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)
Loss Contingencies [Line Items]
Number of class actions filed (in legal matters) | lawsuit	3
Number of class actions dismissed (in legal matters) | lawsuit	2
Fees To Former European Distributor
Loss Contingencies [Line Items]
Accrued liabilities		$ 7,800,000
Fees To Former European Distributor | Minimum
Loss Contingencies [Line Items]
Commitment due in next twelve months			$ 5,000,000
Fees To Former European Distributor | Maximum
Loss Contingencies [Line Items]
Commitment due in next twelve months			$ 55,000,000

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Leases [Abstract]
Option to extend lease, maximum number of years	5 years		5 years
Operating lease cost	$ 1.2		$ 3
Rent expense		$ 0.9		$ 2.6
Operating cash outflows from operating leases	$ 1		$ 2.6
Weighted average remaining lease term	4 years 1 month 6 days		4 years 1 month 6 days
Weighted average discount rate	6.20%		6.20%

Leases - Future Minimum Undisco

Leases - Future Minimum Undiscounted Lease Payments (Details) $ in Thousands	Sep. 30, 2019USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2019 (remaining)	$ 984
2020	3,628
2021	4,118
2022	3,658
2023	1,278
Thereafter	2,216
Total future minimum lease payments	15,882
Less: imputed interest	(1,991)
Present value of future minimum lease payments	$ 13,891

Leases - Summary of ROU Assets

Leases - Summary of ROU Assets and Operating Lease Liabilities (Details) $ in Thousands	Sep. 30, 2019USD ($)
Leases [Abstract]
Other assets	$ 12,190
Accrued expenses and other current liabilities	2,341
Other liabilities	11,550
Present value of future minimum lease payments	$ 13,891

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense Related to Share-Based Awards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 6,626	$ 16,088	$ 20,704	$ 31,205
Unamortized Expense	45,446		45,446
Employee stock purchase plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	443	296	1,162	884
Unamortized Expense	295		$ 295
Share-based compensation arrangement by share-based payment award, equity instruments other than options, outstanding, weighted average remaining expense period			6 days
Stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,469	3,957	$ 4,691	8,587
Unamortized Expense	9,225		$ 9,225
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, exercisable, weighted average remaining expense period			2 years 6 months
Restricted stock units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	4,714	$ 11,835	$ 14,851	$ 21,734
Unamortized Expense	$ 35,926		$ 35,926
Share-based compensation arrangement by share-based payment award, equity instruments other than options, outstanding, weighted average remaining expense period			2 years

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019
Number of Options
Beginning balance (in shares)	3,077,624
Granted (in shares)	125,640
Exercised (in shares)	(1,192,397)
Forfeited / Expired (in shares)	(124,198)
Ending balance (in shares)	1,886,669
Vested, at end of period (in shares)	1,447,398
Vested or expected to vest, at end of period (in shares)	1,835,967
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 39.16
Granted (in dollars per share)	93.16
Exercised (in dollars per share)	34.68
Forfeited / Expired (in dollars per share)	50.58
Ending balance (in dollars per share)	44.84
Vested, at end of period (in dollars per share)	$ 38.25
Aggregate Intrinsic Value
Exercised	$ 99,206
Ending balance	226,571
Vested, at end of period	183,351
Vested or expected to vest, at end of period	$ 222,101
Weighted Average Remaining Contractual Term (Years)
Options outstanding, weighted average remaining contractual term	5 years 7 months 6 days
Options vested, weighted average remaining contractual term	4 years 9 months 18 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Restricted Stock Units (Details) - Restricted stock units	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	752,207
Granted (in shares) | shares	317,212
Vested (in shares) | shares	(317,481)
Forfeited (in shares) | shares	(69,013)
Ending balance (in shares) | shares	682,925
Weighted Average Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 55.02
Granted (in dollars per share) | $ / shares	94.68
Vested (in dollars per share) | $ / shares	45.29
Forfeited (in dollars per share) | $ / shares	67.34
Ending balance (in dollars per share) | $ / shares	$ 76.72

Interest Expense - Interest Exp

Interest Expense - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Contractual coupon interest	$ 2,553	$ 2,440	$ 7,477	$ 7,382
Accretion of debt discount	8,202	6,712	22,202	19,840
Amortization of debt issuance costs	700	661	2,072	1,950
Capitalized interest	(2,085)	(2,967)	(8,124)	(7,128)
Interest expense, net of portion capitalized	9,370	6,846	23,627	22,044
Amortization of debt discount and issuance costs	8,902	7,373	24,274	21,790
Total interest expense related to convertible debt	11,455	9,813	31,751	29,172
1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	1,384	1,362	4,152	4,129
Amortization of debt discount and issuance costs	4,021	3,746	11,824	11,001
Total interest expense related to convertible debt	$ 5,405	$ 5,108	$ 15,976	$ 15,130
Debt, interest rate	1.375%	1.375%	1.375%	1.375%	1.375%
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	$ 961	$ 1,078	$ 3,117	$ 3,234
Amortization of debt discount and issuance costs	3,006	3,627	10,575	10,729
Total interest expense related to convertible debt	$ 3,967	$ 4,705	$ 13,692	$ 13,963
Debt, interest rate	1.25%	1.25%	1.25%	1.25%	1.25%
2% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest				$ 19
Amortization of debt discount and issuance costs				60
Total interest expense related to convertible debt				$ 79
Debt, interest rate	2.00%		2.00%
0.375% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	$ 208		$ 208
Amortization of debt discount and issuance costs	1,875		1,875
Total interest expense related to convertible debt	$ 2,083		$ 2,083
Debt, interest rate	0.375%		0.375%		0.375%

Income Tax Expense - Narrative

Income Tax Expense - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective tax rate	24.60%	10.50%	14.10%	16.60%

Uncategorized Items - podd-2019

Label	Element	Value
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 20,349,000
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 20,349,000