Insulet (PODD) 10-K 22 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 16, 2018	Jun. 30, 2017
Document Documentand Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	PODD
Entity Registrant Name	INSULET CORPORATION
Entity Central Index Key	1,145,197
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		58,391,036
Entity Public Float			$ 3
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 272,577	$ 137,174
Short-term investments	167,479	161,396
Accounts receivable, net	53,373	28,803
Inventories	33,793	35,514
Prepaid expenses and other current assets	9,949	7,073
Total current assets	537,171	369,960
Long-term investments	125,549	0
Property and equipment, net	107,864	44,753
Other intangible assets, net	4,351	2,041
Goodwill	39,840	39,677
Other assets	1,969	216
Total assets	816,744	456,647
Current Liabilities
Accounts payable	24,413	13,160
Accrued expenses and other current liabilities	59,256	41,228
Deferred revenue	2,356	1,309
Total current liabilities	86,025	55,697
Long-term debt, net	566,173	332,768
Other long-term liabilities	6,030	5,032
Total liabilities	658,228	393,497
Commitments and contingencies
Stockholders’ Equity
Preferred stock, $.001 par value: Authorized 5,000,000 shares at December 31, 2016 and 2015. Issued and outstanding: zero shares at December 31, 2016 and 2015	0	0
Common stock, $.001 par value: Authorized: 1,000,000 shares at December 31, 2016 and 2015. Issued and outstanding: 57,457,967 and 56,954,830 shares at December 31, 2016 and 2015, respectively	58	57
Additional paid-in capital	866,206	744,243
Accumulated other comprehensive loss	(493)	(726)
Accumulated deficit	(707,255)	(680,424)
Total stockholders’ equity	158,516	63,150
Total liabilities and stockholders’ equity	$ 816,744	$ 456,647

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	58,319,348	57,457,967
Common stock, outstanding	58,319,348	57,457,967

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenue	$ 463,768	$ 366,989	$ 263,893
Cost of revenue	186,599	155,903	130,622
Gross profit	277,169	211,086	133,271
Operating expenses:
Research and development	74,452	55,710	43,208
Sales and marketing	121,617	94,483	78,407
General and administrative	88,487	71,597	60,392
Total operating expenses	284,556	221,790	182,007
Operating loss	(7,387)	(10,704)	(48,736)
Interest expense	21,211	14,388	12,712
Interest income and other, net	2,633	825	58
Loss on extinguishment of long-term debt	609	2,551	0
Interest and other income (expense), net	(19,187)	(16,114)	(12,654)
Loss from continuing operations before income taxes	(26,574)	(26,818)	(61,390)
Income tax expense	(257)	(392)	(212)
Net loss from continuing operations	(26,831)	(27,210)	(61,602)
Loss from discontinued operations, net of tax ($408 and $79 for the years ended December 31, 2016 and 2015, respectively)	0	(1,669)	(11,918)
Net loss	$ (26,831)	$ (28,879)	$ (73,520)
Net loss from continuing operations per share basic and diluted (USD per share)	$ (0.46)	$ (0.48)	$ (1.08)
Net loss from discontinued operations per share basic and diluted (USD per share)	$ 0	$ (0.03)	$ (0.21)
Weighted-average number of shares used in calculating net loss per share (shares)	58,003,434	57,251,377	56,785,646

Consolidated Statements of Ope5

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Income tax expense from discontinued operations	$ 408	$ 79

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (26,831)	$ (28,879)	$ (73,520)
Other comprehensive loss, net of tax
Foreign currency translation adjustment, net of tax	565	135	(641)
Unrealized loss on available-for-sale securities, net of tax	(332)	(207)	0
Total other comprehensive income (loss), net of tax	233	(72)	(641)
Total comprehensive loss	$ (26,598)	$ (28,951)	$ (74,161)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	2% Convertible Senior Notes	1.25% Convertible Senior Notes	1.375% Convertible Senior Notes	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital2% Convertible Senior Notes	Additional Paid-in Capital1.25% Convertible Senior Notes	Additional Paid-in Capital1.375% Convertible Senior Notes	Accumulated Deficit	Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 83,829				$ 56	$ 661,811				$ (578,025)	$ (13)
Beginning balance (in shares) at Dec. 31, 2014					56,299,022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	34,051				$ 57	686,193				(651,545)	(654)
Exercise of options to purchase common stock (in shares)					449,149
Exercise of options to purchase common stock	7,199				$ 1	7,198
Issuance for employee stock purchase plan (in shares)					22,039
Issuance for employee stock purchase plan	652					652
Stock-based compensation expense	19,178					19,178
Restricted stock units vested, net of shares withheld for taxes (in shares)					184,620
Restricted stock units vested, net of shares withheld for taxes	(2,646)					(2,646)
Net loss	(73,520)									(73,520)
Other comprehensive income (loss)	(641)										(641)
Beginning balance (in shares) at Dec. 31, 2015					56,954,830
Beginning balance at Dec. 31, 2015	34,051				$ 57	686,193				(651,545)	(654)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	34,051				57	686,193				(651,545)	(654)
Beginning balance	63,150				$ 57	744,243				(680,424)	(726)
Exercise of options to purchase common stock (in shares)					242,962
Exercise of options to purchase common stock	4,832				$ 0	4,832
Issuance for employee stock purchase plan (in shares)					30,949
Issuance for employee stock purchase plan	802					802
Stock-based compensation expense	23,638					23,638
Restricted stock units vested, net of shares withheld for taxes (in shares)					229,226
Restricted stock units vested, net of shares withheld for taxes	(2,866)					(2,866)
Net impact of conversion of Notes		$ (32,865)	$ 64,509				$ (32,865)	$ 64,509
Net loss	(28,879)									(28,879)
Other comprehensive income (loss)	$ (72)										(72)
Beginning balance (in shares) at Dec. 31, 2016	57,457,967				57,457,967
Beginning balance at Dec. 31, 2016	$ 63,150				$ 57	744,243				(680,424)	(726)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	63,150				57	744,243				(680,424)	(726)
Beginning balance	$ 158,516				$ 58	866,206				(707,255)	(493)
Exercise of options to purchase common stock (in shares)	505,207				505,207
Exercise of options to purchase common stock	$ 13,988				$ 1	13,987
Issuance for employee stock purchase plan (in shares)					59,134
Issuance for employee stock purchase plan	1,817					1,817
Stock-based compensation expense	31,941					31,941
Restricted stock units vested, net of shares withheld for taxes (in shares)					297,040
Restricted stock units vested, net of shares withheld for taxes	(4,054)					(4,054)
Net impact of conversion of Notes		$ (39,186)		$ 117,458			$ (39,186)		$ 117,458
Net loss	(26,831)									(26,831)
Other comprehensive income (loss)	$ 233										233
Beginning balance (in shares) at Dec. 31, 2017	58,319,348				58,319,348
Beginning balance at Dec. 31, 2017	$ 158,516				$ 58	866,206				(707,255)	(493)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 158,516				$ 58	$ 866,206				$ (707,255)	$ (493)

Consolidated Statements of Sto8

Consolidated Statements of Stockholders' Equity (Parenthetical)	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2014
2% Convertible Senior Notes
Debt, interest rate	2.00%	2.00%		2.00%
1.25% Convertible Senior Notes
Debt, interest rate	1.25%	1.25%	1.25%
1.375% Convertible Senior Notes
Debt, interest rate	1.375%

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)		Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)
Cash flows from operating activities
Net loss	$ (26,831)		$ (28,879)		$ (73,520)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	13,854		13,833		15,838
Non-cash interest expense	18,008		10,068		7,678
Stock-based compensation expense	31,941		23,617		19,178
Loss on extinguishment of long-term debt	609		2,551		0
Provision for bad debts	1,922		2,070		1,184
Impairments and other	89		6,234		9,086
Changes in operating assets and liabilities:
Accounts receivable	(26,322)		12,551		(9,793)
Inventories	1,689		(24,103)		(722)
Deferred revenue	1,061		(849)		809
Prepaid expenses and other assets	(3,328)		(2,621)		(1,460)
Accounts payable, accrued expenses and other current liabilities	27,313		639		17,986
Other long-term liabilities	1,202		800		1,184
Net cash provided by (used in) operating activities	41,207	[1]	15,911	[1]	(12,552)	[1]
Cash flows from investing activities
Purchases of property, equipment and software	(77,226)	[2]	(22,115)	[2]	(10,608)	[2]
Purchases of investments	(297,965)		(177,654)		0
Receipts from the maturity or sale of investments	164,394		16,045		0
Proceeds from divestiture of business, net	0		5,714		0
Acquisition of business	0		0		(4,715)
Net cash used in investing activities	(210,797)		(178,010)		(15,323)
Cash flows from financing activities
Principal payments of capital lease obligations	(269)		(5,518)		(5,576)
Proceeds from issuance of convertible notes, net of issuance costs	391,638		333,725		0
Repayment of convertible notes	(98,572)		(153,628)		0
Proceeds from exercise of stock options and issuance of common stock under employee stock purchase plan	15,804		4,854		7,851
Payment of withholding taxes in connection with vesting of restricted stock units	(4,054)		(2,866)		(2,646)
Net cash provided by (used in) financing activities	304,547		176,567		(371)
Effect of exchange rate changes on cash	446		34		(275)
Net increase (decrease) in cash, cash equivalents and restricted cash	135,403		14,502		(28,521)
Cash, cash equivalents and restricted cash, beginning of year	137,174	[3]	122,672	[3]	151,193	[3]
Cash, cash equivalents and restricted cash, end of year	272,577	[3]	137,174	[3]	122,672	[3]
Supplemental disclosure of cash flow information
Cash paid for interest	2,476		3,687		4,025
Cash paid for taxes	462		932		109
Non-cash investing and financing activities
Purchases of property and equipment under capital lease	0		0		5,721
Purchases of property, equipment and software, previously recorded in accounts payable	2,000		4,000
Restricted cash	500		1,200		1,200
1.375% Convertible Senior Notes
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Non-cash interest expense	1,998
Non-cash investing and financing activities
Allocation to equity for conversion feature for issuance of convertible debt	120,710		0		0
1.25% Convertible Senior Notes
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Non-cash interest expense	13,549
Non-cash investing and financing activities
Allocation to equity for conversion feature for issuance of convertible debt	0		66,689		0
2% Convertible Senior Notes
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Non-cash interest expense	2,461
Non-cash investing and financing activities
Allocation to equity for conversion feature for the repurchase of 2% convertible notes	$ (39,186)		$ (32,865)		$ 0
[1]	Includes activity related to discontinued operations for the years ended December 31, 2016 and 2015. See Note 19 to the consolidated financial statements for discussion of discontinued operations.
[2]	(2) Cash outflows from purchases of property, equipment and software for the year ended December 31, 2017 include $2.0 million of purchases made in prior periods that were included in accounts payable and accrued expenses as of December 31, 2016 and exclude $4.0 million of purchases made during the year ended December 31, 2017 that were included in accounts payable and accrued expenses as of December 31, 2017.
[3]	Cash and cash equivalents includes restricted cash amounts totaling $0.5 million, $1.2 million and $1.2 million as of December 31, 2017, 2016 and 2015, respectively. See Note 2 to the consolidated financial statements.

Consolidated Statements of Ca10

Consolidated Statements of Cash Flows (Parenthetical)	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2014
1.375% Convertible Senior Notes
Debt, interest rate	1.375%
2% Convertible Senior Notes
Debt, interest rate	2.00%	2.00%		2.00%
1.25% Convertible Senior Notes
Debt, interest rate	1.25%	1.25%	1.25%

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	Nature of the Business Insulet Corporation, the "Company," is primarily engaged in the development, manufacturing and sale of its proprietary Omnipod Insulin Management System (the “Omnipod System”), an innovative, discreet and easy-to-use continuous insulin delivery system for people with insulin-dependent diabetes. The Omnipod System features a small, lightweight, self-adhesive disposable tubeless Omnipod device, which is worn on the body for approximately three days at a time, and its wireless companion, the handheld Personal Diabetes Manager (“PDM”). Conventional insulin pumps require people with insulin-dependent diabetes to learn to use, manage and wear a number of cumbersome components, including up to 42 inches of tubing. In contrast, the Omnipod System features only two discreet, easy-to-use devices that eliminate the need for a bulky pump and tubing, provides for virtually pain-free automated cannula insertion, communicates wirelessly and integrates a blood glucose meter. The Company believes that the Omnipod System’s unique proprietary design and features allow people with insulin-dependent diabetes to manage their diabetes with unprecedented freedom, comfort, convenience, and ease. Commercial sales of the Omnipod System began in the United States in 2005. The Company sells the Omnipod System in the United States through direct sales to customers or through its distribution partners. The Omnipod System is currently available in multiple countries in Europe, as well as in Canada and Israel. To lower manufacturing costs, increase supply redundancy, add capacity closer to its largest customer base and support growth, the Company is constructing a highly-automated manufacturing facility in Acton, Massachusetts with planned production out of the facility beginning in early 2019. The facility will also serve as the Company's global headquarters. The Company announced on July 20, 2017 its plans to assume, on July 1, 2018, all commercial activities (including, among other things, distribution, sales, marketing, training and support) of its Omnipod System across Europe following the expiration of its distribution agreement with Ypsomed Distribution AG ("Ypsomed" or the "European distributor") on June 30, 2018. Until the expiration of the distribution agreement, the Company's current distribution agreement for its Omnipod products in Europe will remain in effect. The Company will be required to pay to the European distributor a per unit fee for sales of the Company's Omnipod device, over the twelve months following the expiration of the distribution agreement, to identified customers, as that term is defined in the distribution agreement, of the European distributor who had previously entered into an agreement with the distributor for the purchase of Omnipod devices. The Company expects to recognize a liability for this fee as qualifying sales of its Omnipod device are made to these identified customers during the twelve-month period beginning July 1, 2018. In addition to using the Omnipod for insulin delivery, the Company also partners with global pharmaceutical and biotechnology companies to tailor the Omnipod System technology platform for the delivery of subcutaneous drugs across multiple therapeutic areas. The Company acquired Neighborhood Holdings, Inc. and its wholly-owned subsidiaries (collectively, “Neighborhood Diabetes”) in June 2011 . Through Neighborhood Diabetes, the Company provided customers with blood glucose testing supplies, traditional insulin pumps, pump supplies and pharmaceuticals and had the ability to process claims as either durable medical equipment or through pharmacy benefits. In February 2016, the Company sold Neighborhood Diabetes to Liberty Medical LLC ("Liberty Medical"). Additional information regarding the disposition and treatment of the Neighborhood Diabetes business as discontinued operations is provided in Note 19 to these consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates in Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States ("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. The most significant estimates used in these financial statements include the valuation of stock-based compensation expense; the fair value of intangible assets acquired in businesses combinations; the valuation of inventory; the valuation of deferred revenue; the calculation of gains and losses, if any, on the retirement or conversion of convertible debt; the estimated useful lives of property and equipment and intangible assets; the amount of internal use software development costs that qualify for capitalization; the valuation allowance related to deferred income taxes, the estimated amount, if any, of accrued contingent liabilities as well as warranty and doubtful accounts allowance reserve calculations. Actual results may differ from those estimates. Principles of Consolidation and Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, primarily related to internal-use software intangible assets, have been made to prior period amounts to conform to the current period financial statement presentation. Foreign Currency Translation For foreign operations, asset and liability accounts are translated at exchange rates as of the balance sheet date; income and expenses are translated using weighted average exchange rates for the reporting period. Resulting translation adjustments are reported in accumulated other comprehensive loss, a separate component of stockholders' equity. Gains and losses arising from transactions and translation of period-end balances denominated in currencies other than the functional currency, primarily the Canadian dollar, are included in interest and other income (expense), net, and were not material for fiscal years 2017 , 2016 and 2015 . Cash and Cash Equivalents For the purpose of the financial statement classification, the Company considers all highly-liquid investment instruments with original maturities of 90 days or less, when purchased, to be cash equivalents. Cash equivalents include money market mutual funds, corporate bonds, and certificates of deposit which are carried at cost which approximates their fair value. Included in the Company's cash and cash equivalents are restricted cash amounts set aside for collateral on outstanding letters of credit related to lease obligations totaling $0.5 million as of December 31, 2017 and $1.2 million as of December 31, 2016 . Investments in Marketable Securities Short-term and long-term investment securities consist of available-for-sale marketable securities and are carried at fair value with unrealized gains or losses included as a component of other comprehensive loss in stockholders' equity. Investments, exclusive of cash equivalents, with a stated maturity date of more than one year from the balance sheet date and that are not expected to be used in current operations, are classified as long-term investments. Short-term and long-term investments include U.S. government and agency bonds, corporate bonds, and certificates of deposit. The Company reviews investments for other-than-temporary impairment when the fair value of an investment is less than its amortized cost. If an available-for-sale security is other than temporarily impaired, the loss is charged to earnings. Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful life of the respective assets. Leasehold improvements are amortized over their useful life or the life of the lease, whichever is shorter. Assets acquired under capital leases are amortized in accordance with the respective class of owned assets and the amortization is included with depreciation expense. Maintenance and repair costs are expensed as incurred. Business Combinations The Company recognizes the assets and liabilities assumed in business combinations on the basis of their fair values at the date of acquisition. The Company assesses the fair value of assets, including intangible assets, using a variety of methods and each asset is measured at fair value from the perspective of a market participant. The method used to estimate the fair values of intangible assets incorporates significant assumptions regarding the estimates a market participant would make in order to evaluate an asset, including a market participant’s use of the asset and the appropriate discount rates for a market participant. Assets recorded from the perspective of a market participant that are determined to not have economic use for the Company are expensed immediately. Any excess purchase price over the fair value of the net tangible and intangible assets acquired is allocated to goodwill. Transaction costs and restructuring costs associated with a business combination are expensed as incurred. Segment Reporting Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated on a regular basis by the chief operating decision-maker ("CODM") in deciding how to allocate resources to an individual segment and in assessing performance of the segment. The Company has concluded that its Chief Executive Officer is the CODM as he is the ultimate decision maker for key operating decisions, determining the allocation of resources and assessing the financial performance of the Company. These decisions, allocations and assessments are performed by the CODM using consolidated financial information. Consolidated financial information is utilized by the CODM as the Company’s current product offering primarily consists of the Omnipod System and drug delivery. The Company’s products are relatively consistent and manufacturing is centralized and consistent across product offerings. Based on these factors, key operating decisions and resource allocations are made by the CODM using consolidated financial data and as such the Company has concluded that it operates as one segment. Goodwill Goodwill represents the excess of the cost of acquired businesses over the fair value of identifiable net assets acquired. The Company follows the provisions of Financial Accounting Standards Board ("FASB") ASC 350-20, Intangibles - Goodwill and Other (“ASC 350-20”) whereby the Company performs an assessment of its goodwill for impairment on at least an annual basis or whenever events or changes in circumstances indicate there might be impairment. The Company's annual impairment test date is October 1st. Goodwill is evaluated for impairment at the reporting unit level. As the Company operates in one segment, the Company has considered whether that segment contains multiple components which represent separate reporting units. The Company has concluded that it has a single reporting unit. In reaching this conclusion, the Company considered how components of the business are managed, whether discrete financial information at the component level is reviewed on a regular basis by segment management and whether components may be aggregated based on economic similarity. In performing that annual goodwill test, the Company utilizes the two-step approach as currently prescribed by ASC 350-20. The first step compares the carrying value of the reporting unit to its fair value. If the reporting unit’s carrying value exceeds its fair value, the Company would perform the second step and record an impairment loss to the extent that the carrying value of the reporting unit's goodwill exceeds its implied fair value. There were no impairments of goodwill during the years ended December 31, 2017 , 2016 or 2015 . The following table presents the change in carrying amount of goodwill during the period indicated: Years Ended December 31, (In thousands) 2017 2016 Goodwill: Beginning balance $ 39,677 $ 39,607 Foreign currency adjustment 163 70 Ending balance $ 39,840 $ 39,677 Revenue Recognition The Company generates the majority of its revenue from sales of its Omnipod System directly to patients and through third-party distributors. Revenue recognition requires that persuasive evidence of a sales arrangement exists, delivery of goods occurs through transfer of title and risk and rewards of ownership, the selling price is fixed or determinable and collectability is reasonably assured. With respect to these criteria: • The evidence of an arrangement generally consists of a physician order form, a patient information form and, if applicable, third-party insurance approval for sales directly to patients or a purchase order for sales to a third-party distributor. • Revenue is recognized when title and risk and rewards of ownership have transferred to the customer. • The selling prices for all sales are fixed and agreed with the patient or third-party distributor and, if applicable, the patient’s third-party insurance provider(s) prior to shipment and are based on established list prices or, in the case of certain third-party insurers, contractually agreed upon prices. Provisions for discounts, rebates and other adjustments to customers are established as a reduction to revenue in the same period the related sales are recorded. The Company offers a 45 -day right of return for sales of its Omnipod System in the United States, and a 90 -day right of return for sales of its Omnipod System in Canada to new patients and defers revenue to reflect estimated sales returns in the same period that the related product sales are recorded. Returns are estimated through a comparison of the Company’s historical return data to its related sales. Historical rates of return are adjusted for known or expected changes in the marketplace when appropriate. When doubt exists about reasonable assuredness of collectability from specific customers, the Company defers revenue from sales of products to those customers until payment is received. The Company had deferred revenue of $3.2 million and $1.9 million as of December 31, 2017 and 2016 , respectively. Deferred revenue included $0.9 million and $0.6 million classified in other long-term liabilities as of December 31, 2017 and 2016 , respectively. Deferred revenue relates to undelivered elements within certain of the Company's developmental arrangements and other instances where the Company has not yet met the revenue recognition criteria. Collaborative Arrangements The Company enters into collaborative arrangements for ongoing initiatives to develop products. Although the Company does not consider any individual alliance to be material, the following more notable alliances are described below. Eli Lilly and Concentrated insulins : In May 2013, the Company entered into an agreement with Eli Lilly and Company (Eli Lilly) to develop a new version of the Omnipod System specifically designed to deliver Humulin ® R U-500 insulin, a concentrated form of insulin used by people with highly insulin resistant Type 2 diabetes. In January 2016, the Company entered into a development agreement with Eli Lilly to develop a new version of Insulet's Omnipod tubeless insulin delivery system, specifically designed to deliver Lilly's Humalog ® 200 units/mL insulin, a concentrated form of insulin used by higher insulin-requiring patients with diabetes that provides the same dose of insulin in half the volume of Lilly's Humalog ® U-100 insulin. Under the terms of these arrangements, the parties share the responsibility of the permissible costs that are incurred. Any amounts incurred in excess of the permissible shared costs that are the responsibility of one party becomes due and payable by the other party. Consideration received and payments made by the Company under the terms of the arrangements are recorded within research and development expense. Shipping and Handling Costs The Company does not typically charge its customers for shipping and handling costs associated with shipping its product to its customers unless non-standard shipping and handling services are requested. These shipping and handling costs are included in general and administrative expenses and were $5.0 million , $4.1 million and $3.7 million in the years ended December 31, 2017 , 2016 and 2015 , respectively. Concentration of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents, short-term and long-term investments in marketable securities and accounts receivable. The Company maintains the majority of its cash and short-term and long-term investments with one financial institution. Accounts are partially insured up to various amounts mandated by the Federal Deposit Insurance Corporation or by the foreign country where the account is held. The Company purchases Omnipod Systems from Flex Ltd., its single source supplier. As of December 31, 2017 and December 31, 2016 , liabilities to this vendor represented approximately 20% and 16% , respectively, of the combined balance of accounts payable, accrued expenses and other current liabilities. Revenue for customers comprising more than 10% of total revenue were as follows: Twelve Months Ended December 31, 2017 2016 2015 Amgen, Inc. 15% 17% 10% Ypsomed Distribution AG 22% 16% 12% RGH Enterprises, Inc. 11% 10% 13% Recently Adopted Accounting Standards During 2017, the Company retrospectively adopted Accounting Standards Update ("ASU") 2016-19, Technical Corrections and Improvements, which included clarification that the license of internal-use software shall be accounted for as the acquisition of an intangible asset. As a result of adoption, the Company reclassified $4.1 million of gross internal-use software costs, net of accumulated amortization of $2.6 million , from property and equipment to other intangible assets as of December 31, 2016. Effective January 1, 2017, the Company adopted ASU 2015-11, Simplifying the Measurement of Inventory, which requires entities to measure most inventory at the lower of cost and net realizable value. The adoption of this guidance did not have a material impact on the consolidated financial statements. Effective January 1, 2017, the Company adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09") using the modified retrospective method. ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The adoption of ASU 2016-09 resulted in the Company increasing its deferred tax assets by approximately $23.8 million , which was offset by a full valuation allowance. The adoption of the standard did not have a material impact on the Company's consolidated financial statements. Effective January 1, 2017, the Company adopted ASU 2016-18, Restricted Cash (a consensus of the Emerging Issues Task Force) ("ASU 2016-18") using the retrospective transition method. ASU 2016-18 requires the statement of cash flows to show the changes in the total of cash, cash equivalents, and restricted cash. There was no significant impact on the statement of cash flows upon the adoption of ASU 2016-18. Accounting Pronouncements Issued and Not Yet Adopted as of December 31, 2017 In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09"). ASU 2014-09 and its related amendments (collectively referred to as ASC 606) requires that an entity recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Under this guidance, an entity makes additional estimates regarding performance conditions and the allocation of variable consideration and must evaluate whether revenue derived from a contract should be recognized at a point in time or over time. The Company adopted the standard as of the required effective date of January 1, 2018 using the modified retrospective method. Under this method, the new guidance was applied to contracts that were not yet completed as of January 1, 2018 with the cumulative effect of initially applying the guidance recognized through accumulated deficit as the date of initial application. In addition to the enhanced footnote disclosures related to customer contracts, the Company anticipates that the most significant impact of the new standard will relate to the timing of revenue recognition relative to a portion of its drug delivery product line, the deferral and amortization of contract acquisition costs such as commissions and a material right granted to the Company's European distributor in 2010. The quantitative ranges provided below are estimates of the expected effects of the Company’s adoption of ASC 606 as of the time of preparation of this Annual Report on Form 10-K. The anticipated accounting impacts described below will have no impact on cash flows. i. Drug Delivery Revenue. The adoption of ASC 606 will accelerate the timing of revenue recognition relative to a portion of the Company's drug delivery product line whereby revenue will be recognized as the product is produced pursuant to the customer’s firm purchase commitments as the Company has an enforceable right to payment for performance completed to date and the inventory has no alternative use to the Company. This guidance is in contrast to legacy accounting guidance whereby revenue is recognized when the product is shipped to the customer. Upon the adoption of ASC 606 on January 1, 2018, the Company expects to record a contract asset on its consolidated balance sheet of approximately $4 million to $6 million to reflect revenue that would have been recognized upon shipment of the product in 2018 under ASC 605 but will not be under ASC 606 as it would have been recognized in 2017 as the product was produced. The impact on the Company's drug delivery revenue in 2018 and forward will depend on the timing of drug delivery inventory production levels. ii. Material Right. The adoption of ASC 606 will require the Company to record a contract liability on January 1, 2018 of approximately $1 million to $3 million associated with a volume-based pricing discount granted to the Company's European distributor at the outset of the distribution contract in 2010. The contract liability will be classified as deferred revenue and will be recognized as revenue through the completion of the distributor contract during the first half of 2018. iii. Contract Acquisition Costs. The adoption of ASC 606 will impact the treatment of contract acquisition costs, such as commissions, which will be capitalized and amortized over the expected period of benefit. Upon adoption, the Company expects to increase its current and other assets by approximately $18 million to $20 million for the net value of cumulative commissions paid prior to adoption less amortization to date. The new guidance will likely have an accretive impact to the Company's earnings in 2018 as the Company continues to increase its customer base. The deferred tax assets and liabilities resulting from these adjustments will be substantially offset by an associated adjustment to the Company valuation allowance. Therefore, as the Company currently maintains a full valuation allowance against its domestic net deferred tax assets, the Company does not expect the adoption of ACS 606 to have a significant impact on its deferred tax balances or income tax expense in 2018. Effective January 1, 2018, the Company adopted ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"). ASU 2016-01 changes the current GAAP model for the accounting of equity investments, whereby equity investments with readily determinable fair value will be carried at fair value with changes reported in net income (loss) as opposed to other comprehensive income (loss). The classification and measurement guidance was effective January 1, 2018 for the Company. As the Company held no available for sale equity investments on December 31, 2017, there was no impact on the consolidated financial statements upon the adoption of ASU 2016-01. Effective January 1, 2018, the Company adopted ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) ("ASU 2016-15"). ASU 2016-15 clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows. The guidance also clarifies how the predominance principle should be applied when cash receipts and cash payments have aspects of more than one class of cash flows. The Company does not expect that the adoption of this guidance will have an impact on the consolidated statement of cash flows. Effective January 1, 2018, the Company adopted ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting ("ASU 2017-09"). ASU 2017-09 specifies the types of changes to the terms or conditions of a share-based payment award that require an entity to apply modification accounting in accordance with Topic 718. The new standard is effective for the Company on January 1, 2018 and early adoption is permitted. The adoption of ASU 2017-09 did not have an impact on the Company's consolidated financial statements. Effective January 1, 2018, the Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory ("ASU 2016-16"). ASU 2016-16 requires than an entity recognized the income tax effects of an intra-entity transfer of an asset, other than inventory, when the transfer occurs as opposed to when the asset is sold to a third party. The Company does not expect that the adoption of this guidance will have a material impact on the consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12"). ASU 2017-12 updates the current hedge accounting guidance with the objective of improving the financial reporting of hedging activities by better portraying the economic results of an entity's risk management activities in its financial statements. The new guidance is effective for the Company on January 1, 2019 and early adoption is permitted. The Company is currently evaluating the impact of ASU 2017-12 on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases ("ASU 2016-02"). ASU 2016-02 requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. The new guidance will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for the Company on January 1, 2019 and is expected to be applicable to all leases in place as of the beginning of the earliest reporting period. The Company does not expect to early-adopt the guidance. While the Company is currently evaluating the impact of ASU 2016-02, the Company currently expects that the new guidance will require an increase in the Company's long-lived assets and a corresponding increase to long-term obligations associated with leased office and warehouse space. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating "Step 2" from the goodwill impairment test, which requires an entity to calculate the implied fair value of goodwill to measure a goodwill impairment charge, and alternatively, requires an entity to measure the impairment of goodwill assigned to a reporting unit as the amount by which the carrying value of the assets and liabilities of the reporting unit, including goodwill, exceeds the reporting unit's fair value. The guidance is effective for annual reporting periods beginning after December 15, 2019, and interim periods within those years. Early adoption is permitted for all entities. The Company is currently evaluating the impact of ASU 2017-04 but does not expect it to be material to the consolidated financial statements. Other Significant Policies: The following table identifies the Company's other significant accounting policies and the note and page where a detailed description of each policy can be found. Fair Value Measurements Note 3 Page Accounts Receivable and Allowance for Doubtful Accounts Note 5 Page Inventories Note 6 Page Product Warranty Costs Note 9 Page Convertible Debt Note 11 Page Commitments and Contingencies Note 12 Page Stock-Based Compensation Note 13 Page

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company applies ASC 820, Fair Value Measurements and Disclosures (“ASC 820”) related to the fair value measurement of certain of its assets and liabilities. ASC 820 defines fair value as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions. When estimating fair value, depending on the nature and complexity of the asset or liability, the Company may use one or all of the following approaches: • Market approach, which is based on market prices and other information from market transactions involving identical or comparable assets or liabilities. • Cost approach, which is based on the cost to acquire or construct comparable assets less an allowance for functional and/or economic obsolescence. • Income approach, which is based on the present value of the future stream of net cash flows. To measure fair value, the Company uses the following fair value hierarchy based on three levels of inputs, as described in ASC 820, of which the first two are considered observable and the last unobservable: 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 in which there is little or no market data available, which require the reporting entity to develop its own assumptions Certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable, accrued expenses and other liabilities are carried at cost, which approximates their fair value because of the short-term maturity of these financial instruments. The following table provides a summary of assets that are measured at fair value as of December 31, 2017 and 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall: Fair Value Measurements (in thousands) Total Level 1 Level 2 Level 3 December 31, 2017 Recurring fair value measurements: Cash equivalents: Money market mutual funds $ 236,936 $ 236,936 $ — $ — U.S. government and agency bonds 5,000 5,000 — — Corporate bonds — — — — Certificates of deposit — — — — Total cash equivalents $ 241,936 $ 241,936 $ — $ — Short-term investments: U.S. government bonds $ 112,076 $ 90,703 $ 21,373 $ — Corporate bonds 47,681 — 47,681 — Certificates of deposit 7,722 — 7,722 — Total short-term investments $ 167,479 $ 90,703 $ 76,776 $ — Long-term investments: U.S. government and agency bonds $ 92,464 $ 49,651 $ 42,813 $ — Corporate bonds 27,812 — 27,812 — Certificates of deposit 5,273 — 5,273 — Total long-term investments $ 125,549 $ 49,651 $ 75,898 $ — December 31, 2016 Recurring fair value measurements: Cash equivalents: Money market mutual funds $ 93,467 $ 93,467 $ — $ — Corporate bonds 4,203 — 4,203 — Certificates of deposit 735 — 735 — Total cash equivalents $ 98,405 $ 93,467 $ 4,938 $ — Short-term investments: U.S. government and agency bonds $ 79,093 $ 49,963 $ 29,130 $ — Corporate bonds 56,653 — 56,653 — Certificates of deposit 25,650 — 25,650 — Total short-term investments $ 161,396 $ 49,963 $ 111,433 $ — Convertible Debt The estimated fair value of the Company's convertible debt is based on the Level 2 quoted market prices for the same or similar issues and includes the impact of the conversion features. The carrying amounts, net of unamortized discounts and issuance costs, and the estimated fair values of the Company's convertible debt as of December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 (in thousands) Carrying Value Estimated Fair Value Carrying Estimated Fair 2% Convertible Senior Notes $ 3,421 $ 5,467 $ 59,737 $ 71,909 1.375% Convertible Senior Notes 276,172 407,652 — — 1.25% Convertible Senior Notes 286,580 450,881 273,031 320,969 Total $ 566,173 $ 864,000 $ 332,768 $ 392,878

Investments

Investments	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The Company's short-term and long-term investments have maturity dates that range from 15 days to 23 months as of December 31, 2017 . Amortized costs, gross unrealized holding gains and losses, and fair values at December 31, 2017 are as follows: (in thousands) Amortized cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2017 U.S. government and agency bonds $ 112,311 $ — $ (235 ) $ 112,076 Corporate bonds 47,713 3 (35 ) 47,681 Certificates of deposit 7,722 — — 7,722 Total short-term investments $ 167,746 $ 3 $ (270 ) $ 167,479 U.S. government and agency bonds $ 92,677 $ — $ (213 ) $ 92,464 Corporate bonds 27,871 — (59 ) 27,812 Certificates of deposit 5,273 — — 5,273 Total long-term investments $ 125,821 $ — $ (272 ) $ 125,549 December 31, 2016 U.S. government and agency bonds $ 79,211 $ — $ (118 ) $ 79,093 Corporate bonds 56,742 — (89 ) 56,653 Certificates of deposit 25,650 — — 25,650 Total short-term investments $ 161,603 $ — $ (207 ) $ 161,396 Total long-term investments $ — $ — $ — $ — The Company's realized gains or losses in the years ended December 31, 2017 and 2016 were insignificant.

Accounts Receivable, Net

Accounts Receivable, Net	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable consist of amounts due from third-party payors, patients, and third-party distributors. The Company records an allowance for doubtful accounts at the time potential collection risk is identified. The Company estimates its allowance based on historical experience, assessment of specific risk, discussions with individual customers or various assumptions and estimates that are believed to be reasonable under the circumstances. The Company believes the reserve is adequate to mitigate current collection risk. Customers that represented greater than 10% of gross accounts receivable as of December 31, 2017 , and 2016 were as follows: As of December 31, 2017 December 31, 2016 Amgen, Inc. 10 % 16 % Ypsomed Distribution AG 31 % 19 % The components of accounts receivable are as follows: (in thousands) As of December 31, 2017 December 31, 2016 Trade receivables $ 55,914 $ 31,714 Allowance for doubtful accounts (2,541 ) (2,911 ) Total accounts receivable $ 53,373 $ 28,803

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Disclosure Components Of Inventories [Abstract]
Inventories	Inventories Inventories are held at the lower of cost or market, determined under the first-in, first-out method, and include the costs of material, labor and overhead. Inventory has been recorded at cost, or net realizable value as appropriate, as of December 31, 2017 and 2016 . The Company reviews inventories for net realizable value based on quantities on hand and expectations of future use. Work in process is calculated based upon a buildup in the stage of completion using estimated labor inputs for each stage in production. The components of inventories are as follows: (in thousands) As of December 31, 2017 December 31, 2016 Raw materials $ 2,146 $ 1,911 Work-in-process 23,918 15,681 Finished goods, net 7,729 17,922 Total inventories $ 33,793 $ 35,514

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment related to continuing operations consist of the following: Estimated Useful Life (Years) As of (in thousands) December 31, 2017 December 31, 2016 Land n/a $ 2,525 $ — Machinery and equipment 2-7 60,878 53,246 Lab equipment 3-7 1,038 694 Computers 3-5 3,659 2,833 Office furniture and fixtures 3-5 2,521 1,960 Leasehold improvement * 1,425 1,126 Construction in process — 87,397 23,859 Total property and equipment $ 159,443 $ 83,718 Less: accumulated depreciation (51,579 ) (38,965 ) Total property and equipment, net $ 107,864 $ 44,753 ____________________________________ * Lesser of lease term or useful life of asset. Depreciation expense related to property and equipment from continuing operations was $12.7 million , $12.6 million and $11.0 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Depreciation expense from discontinued operations was not significant during those same periods. The Company recorded $3.1 million , $0.5 million and $0.2 million of capitalized interest in the years ended December 31, 2017 , 2016 and 2015 . Construction in process mainly consists of construction of the Company's highly-automated manufacturing facility in Acton, Massachusetts with planned production out of the facility beginning in early 2019.

Other Intangible Assets, Net

Other Intangible Assets, Net	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets, Net	Other Intangible Assets, Net The Company’s finite-lived intangible assets are stated at cost less accumulated amortization. The Company assesses its intangible and other long-lived assets for impairment whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. The Company recognizes an impairment loss for intangibles and other finite-lived assets if the carrying amount of a long-lived asset is not recoverable based on its undiscounted future cash flows. Any such impairment loss is measured as the difference between the carrying amount and the fair value of the asset. During 2016, the Company restructured its plan for an internally developed ERP system in order to leverage current third-party software available and scale conversion based on the Company's evolving ERP needs. As a result, the Company recorded a charge of $6.1 million , included in general and administrative expenses, related to this in-process internally developed software. The Company recorded $2.1 million of other intangible assets in 2015 as a result of the acquisition of its Canadian distribution business (see Note 18 for further description). The Company determined that the estimated useful life of the contractual relationship asset is 5 years and is amortizing the asset over its estimated life, based on the expected cash flows of the assets, accordingly. The Company adopted ASU 2016-19 on January 1, 2017 and, as a result, reclassified $4.1 million of gross internal-use software costs, net of accumulated amortization of $2.6 million , from property and equipment to other intangible assets as of December 31, 2016. Other intangible assets consist of the following: As of December 31, 2017 December 31, 2016 (in thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer and contractual relationships $ 2,135 $ (1,764 ) $ 371 $ 1,994 $ (1,466 ) $ 528 Internal use software 7,545 (3,565 ) 3,980 4,064 (2,551 ) 1,513 Total intangible assets $ 9,680 $ (5,329 ) $ 4,351 $ 6,058 $ (4,017 ) $ 2,041 Amortization expense was approximately $1.2 million and $1.2 million for the years ended December 31, 2017 and 2016 , respectively. Amortization expense is recorded in general and administration expenses in the consolidated statements of operations. Amortization expense expected for the next five years and thereafter is as follows: (in thousands) Years Ending December 31, Customer and Contractual Relationships Internal-Use Software Total 2018 $ 165 $ 1,235 $ 1,400 2019 138 984 1,122 2020 68 744 812 2021 — 623 623 2022 — 383 383 Thereafter — 11 11 Total $ 371 $ 3,980 $ 4,351 As of December 31, 2017 , the weighted average amortization periods of the Company’s customer and contractual relationships intangible assets and internal use software intangible assets are approximately 3 years and 4 years, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities related to continuing operations consist of the following: Years Ended December 31, (in thousands) 2017 2016 Employee compensation and related costs $ 34,942 $ 21,999 Professional and consulting services 9,273 6,753 Supplier charges 3,542 2,886 Warranty 1,653 1,642 Accrued interest 2,030 1,303 Accrued freight 1,148 595 Other 6,668 6,050 Total accrued expenses and other current liabilities $ 59,256 $ 41,228 Product Warranty Costs The Company provides a four -year warranty on its PDMs sold in the United States and a five -year warranty on its PDMs sold in Canada and may replace any Omnipod that does 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. Warranty expense is recorded in cost of goods sold on the statement of operations. Cost to service the claims reflects the current product cost. As these estimates are based on historical experience, and the Company continues to introduce new products and versions, the Company also considers the anticipated performance of the product over its warranty period in estimating warranty reserves. A reconciliation of the changes in the Company’s product warranty liability is as follows: Years Ended December 31, (in thousands) 2017 2016 Product warranty liability at the beginning of the period $ 4,388 $ 4,152 Warranty expense 6,127 4,602 Warranty claims settled (5,178 ) (4,366 ) Product warranty liability at the end of the period $ 5,337 $ 4,388 As of (in thousands) December 31, 2017 December 31, 2016 Composition of balance: Short-term $ 1,653 $ 1,642 Long-term 3,684 2,746 Product warranty liability at the end of the period $ 5,337 $ 4,388

Capital Lease Obligations

Capital Lease Obligations	12 Months Ended
	Dec. 31, 2017
Leases, Capital [Abstract]
Capital Lease Obligations	Capital Lease Obligations As of December 31, 2016 , the Company had approximately $13.7 million of manufacturing equipment acquired under capital leases, which is included in property and equipment. During 2017, the Company made final minimum lease payments of $0.3 million and at the expiration of these leases title to the equipment was transferred to the Company. These assets were depreciated on a straight-line basis over 5 years. Depreciation expense related to these assets was $2.7 million , $2.7 million and $2.5 million in the years ended December 31, 2017 , 2016 and 2015 , respectively. As of December 31, 2017, the Company had no assets under capital lease and no future minimum lease payments due under capital leases. The Company recorded $0.4 million and $1.2 million of interest expense on capital leases in the years ended December 31, 2016 , and 2015 , respectively. Interest expense on capital leases was not significant in 2017.

Convertible Debt

Convertible Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Convertible Debt	Convertible Debt The Company had outstanding convertible debt and related deferred financing costs on its consolidated balance sheet as follows: As of (in thousands) December 31, 2017 December 31, 2016 Principal amount of 2.0% Convertible Senior Notes $ 3,664 $ 67,084 Principal amount of 1.25% Convertible Senior Notes 345,000 345,000 Principal amount of 1.375% Convertible Senior Notes 402,500 — Unamortized debt discount (170,448 ) (69,684 ) Deferred financing costs (14,543 ) (9,632 ) Long-term debt, net of discount and issuance costs $ 566,173 $ 332,768 Interest expense related to the convertible notes is as follows: Years Ended December 31, (in thousands) 2017 2016 2015 Contractual coupon interest $ 6,282 $ 4,467 $ 4,025 Accretion of debt discount 15,931 8,800 6,552 Amortization of debt issuance costs 2,077 1,270 1,126 Total interest expense related to convertible notes $ 24,290 $ 14,537 $ 11,703 Interest expense related to convertible notes for the year ended December 31, 2017 is as follows: (in thousands) 1.375% 1.25% 2.0% Total Contractual coupon interest $ 769 $ 4,336 $ 1,177 $ 6,282 Amortization of debt discount and issuance costs 1,998 13,549 2,461 18,008 Total interest expense $ 2,767 $ 17,885 $ 3,638 $ 24,290 1.375% Convertible Senior Notes In November 2017, the Company issued and sold $402.5 million in aggregate principal amount of 1.375% Convertible Senior Notes, due November 15, 2024 (the " 1.375% Notes"). The interest rate on the notes is 1.375% per annum, payable semi-annually in arrears in cash on May 15 and November 15 of each year. Interest began accruing on November 10, 2017 and the first interest payment is due on May 15, 2018. The 1.375% Notes are convertible into the Company’s common stock at an initial conversion rate of 10.7315 shares of common stock per $1,000 principal amount of the 1.375% Notes, which is equivalent to a conversion price of approximately $93.18 per share, subject to adjustment under certain circumstances. The 1.375% Notes will be convertible prior to the close of business on the business day immediately preceding August 15, 2024 only under certain circumstances and during certain periods, and will be convertible on or after August 15, 2024 until the close of business on the second scheduled trading day immediately preceding November 15, 2024, regardless of those circumstances. The Company recorded a debt discount of $120.7 million related to the 1.375% Notes resulting from the allocation of a portion of the proceeds to the fair value of the conversion feature. The debt discount was recorded as additional paid-in capital and the remaining liability reflects a nonconvertible debt borrowing rate of 6.8% per annum. This debt discount is being amortized as non-cash interest expense over the seven year term of the 1.375% Notes. The Company also incurred debt issuance costs and other expenses related to the 1.375% Notes of approximately $10.9 million , of which $3.3 million has been reclassified as a reduction to the value of the conversion feature allocated to equity. The remaining $7.6 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 1.375% Notes. The 1.375% 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 SEC. The additional interest is at a rate of 0.50% 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 1.375% 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. As of December 31, 2017, the Company included $276.2 million , net of unamortized discount and issuance costs, on its consolidated balance sheet in long-term debt related to the 1.375% Notes. 1.25% Convertible Senior Notes In September 2016, the Company issued and sold $345.0 million in principal amount of 1.25% Convertible Senior Notes, due September 15, 2021 . The interest rate on the notes is 1.25% per annum, payable semi-annually in arrears in cash on March 15 and September 15 of each year. The 1.25% Notes are convertible into the Company’s common stock at an initial conversion rate of 17.1332 shares of common stock per $1,000 principal amount of the 1.25% Notes, which is equivalent to a conversion price of approximately $58.37 per share, subject to adjustment under certain circumstances. The 1.25% Notes will be convertible prior to the close of business on the business day immediately preceding June 15, 2021 only under certain circumstances and during certain periods, and will be convertible on or after June 15, 2021 until the close of business on the second scheduled trading day immediately preceding September 15, 2021, regardless of those circumstances. The Company recorded a debt discount of $66.7 million related to the 1.25% Notes which results from allocating a portion of the proceeds to the fair value of the conversion feature. The fair value of the debt discount was estimated using a trinomial lattice model based on the following inputs: Company's stock price, expected volatility, term to maturity, risk-free interest rate, and dividend yield. The debt discount was recorded as additional paid-in capital and the remaining liability reflects the value of the Company’s nonconvertible debt borrowing rate of 5.8% per annum. This debt discount is being amortized as non-cash interest expense over the five year term of the 1.25% Notes. The Company incurred debt issuance costs and other expenses related to this offering of approximately $11.3 million , of which $2.2 million has been reclassified as a reduction to the value of the amount allocated to equity. The remainder is presented as a reduction of debt in the consolidated balance sheet, is being amortized using the effective interest method, and is recorded as non-cash interest expense over the five year term of the 1.25% Notes. The 1.25% 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 SEC. The additional interest is at a rate of 0.50% 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 1.25% 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 a nominal value at the balance sheet date. As of December 31, 2017, the Company included $286.6 million , net of unamortized discount and issuance costs, on its consolidated balance sheet in long-term debt related to the 1.25% Notes. 2% Convertible Senior Notes In June 2014, the Company issued and sold $201.3 million in principal amount of 2% Convertible Senior Notes due June 15, 2019 (the “ 2% Notes”). The interest rate on the notes is 2% per annum, payable semi-annually in arrears in cash on June 15 and December 15 of each year. The 2% Notes are convertible into the Company’s common stock at an initial conversion rate of 21.5019 shares of common stock per $1,000 principal amount of the 2% Notes, which is equivalent to a conversion price of approximately $46.51 per share, subject to adjustment under certain circumstances. Upon issuance of the notes, the Company recorded a debt discount of $35.6 million , which was recorded as additional paid-in capital to reflect the value of the Company’s nonconvertible debt borrowing rate of 6.2% per annum. The debt discount is being amortized as non-cash interest expense over the five year term of the 2% Notes. Financing costs related to this offering were approximately $6.7 million , of which $1.2 million was classified to equity and the remainder was recorded as a reduction to debt in the consolidated balance sheet and is being amortized as non-cash interest expense over the five year term of the 2% Notes. In September 2016, in connection with the issuance of $345 million in principal amount of the 1.25% Notes, the Company repurchased approximately $134.2 million in principal amount of the 2% Notes for $153.6 million . The extinguishment of the 2% Notes was accounted for separately from the issuance of the 1.25% Notes as both transactions were viewed as arm's-length in nature and were not contingent upon one another. The $ 153.6 million paid to extinguish the debt was allocated to debt and equity based on their respective fair values immediately prior to the transaction. The fair value of the debt, which is classified as a Level 3 measurement, was estimated using a trinomial lattice model based on the following inputs: Company's stock price, expected volatility, term to maturity, risk-free interest rate, and dividend yield. The Company allocated $121.4 million of the payment to the debt and $32.9 million to equity. The Company recorded a loss on extinguishment of debt of $2.6 million in connection with the repurchase and redemption of the 2% Notes during the year ended December 31, 2016, representing the excess of the $121.4 million allocated to the debt over its carrying value, net of unamortized debt discount, deferred financing costs and accrued interest. In November 2017, the Company used $98.6 million of the net proceeds from the 1.375% Notes to repurchase approximately $63.4 million principal amount of its outstanding 2.0% Convertible Senior Notes due 2019 (the " 2% Notes") pursuant to individually negotiated transactions. The extinguishment of the 2% Notes was accounted for separately from the issuance of the 1.375% Notes as both transactions were arm's-length in nature and were not contingent upon one another. The amount paid to extinguish these notes was allocated between debt in the amount $59.4 million and equity in the amount of $39.2 million based on their respective fair values immediately prior to the transaction. The fair value of the debt, which is considered a Level 3 measurement, was determined by comparing the effective yield-to-maturity of the repurchased 2% Notes as of the extinguishment date to the market yield for non-convertible debt with similar characteristics. The Company recorded a loss on extinguishment of debt of $0.6 million in connection with the repurchase of the 2% Notes during the year ended December 31, 2017, representing the excess of the amount allocated to the debt over the principal amount of the debt plus accrued interest, net of unamortized debt discount and deferred financing costs. The 2% Notes contain provisions that allow for additional interest to the holders of the notes upon the failure to timely file documents or reports that the Company is required to file with the SEC. The additional interest is at a rate of 0.25% per annum of the principal amount of the notes outstanding for the first 180 days and 0.50% per annum of the principal amount of the notes outstanding for a period up to 360 days. The Company determined that the higher interest 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 a nominal value at the balance sheet date. As of December 31, 2017 , the Company included $3.4 million , net of unamortized discount and issuance costs, on its consolidated balance sheet in long-term debt related to the 2% Notes.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company records a liability in the consolidated financial statements for loss contingencies when a loss is known or considered probable and the amount can be reasonably estimated. If the reasonable estimate of a known or probable loss is a range, and no amount within the range is a better estimate than any other, the minimum amount of the range is accrued. If a loss is reasonably possible but not known or probable, and can be reasonably estimated, the estimated loss or range of loss is disclosed. Operating Leases The Company leases facilities in Massachusetts, California, Tennessee, the United Kingdom, Canada and China. The Company’s leases are accounted for as operating leases. The leases generally provide for a base rent plus real estate taxes and certain operating expenses related to the leases. The Company leases approximately 100,000 square feet of laboratory and office space for its corporate headquarters in Billerica, Massachusetts. The lease expires in November 2022 and contain escalating payments over the life of the lease. Additionally, the Company leases approximately 29,000 square feet of warehousing space in Billerica, Massachusetts under a lease expiring in September 2019. The Company leases other facilities in Canada, China, the United Kingdom, California and Tennessee containing a total of approximately 14,000 square feet under leases expiring from April 2018 to December 2020. Certain of the Company’s operating lease agreements contain scheduled rent increases. Rent expense is recorded using the straight-line method and deferred rent is included in other liabilities in the accompanying consolidated balance sheets. Rental expense from continuing operations under operating leases was $2.8 million , $2.5 million and $1.9 million in the years ended December 31, 2017 , 2016 and 2015 , respectively. The aggregate future minimum lease payments related to these leases as of December 31, 2017 are as follows: (in thousands) Years Ending December 31, Minimum Lease Payments 2018 3,025 2019 2,961 2020 2,611 2021 2,383 2022 2,131 Thereafter — Total $ 13,111 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 current 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”) which remains outstanding, alleges 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. The lawsuit seeks, among other things, compensatory damages in connection with the Company’s allegedly inflated stock price between May 7, 2013 and April 30, 2015, as well as attorneys' fees and costs. 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. Both actions were filed as related actions to the securities class action referenced above, and 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 December 14, 2017, following a series of negotiations, the Company, the individual defendants and their insurers reached an agreement in principle with the plaintiffs in the ATRS matter, individually and on behalf of the respective classes they purport to represent, to settle and release all claims with respect to the matter, subject to final court approval. Under the terms of the agreement in principle, a payment would be made to the plaintiffs and the classes they purport to represent. The Company has accrued fees and expenses in connection with this matter up to and including the amount of any expected residual settlement liability that would not be covered by insurance, and such amount is not material to the Company's consolidated financial statements. The parties have filed a motion for preliminary approval of the settlement with the court and it is currently under review. Although the Company currently believes that the settlement is likely to be consummated and approved, there can be no assurance that the settlement will receive court approval on the terms proposed by the parties. In the event that the settlement is not approved by the court, the Company would not be able to reasonably estimate the possible uninsured loss, or range of uninsured loss, to the Company in connection with an alternative resolution of this matter. 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.

Stock-Based Compensation and St

Stock-Based Compensation and Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation and Stockholders' Equity	Stock-Based Compensation and Stockholders' Equity Stock-Based Compensation The Company accounts for stock-based compensation under the provisions of ASC 718-10, Compensation — Stock Compensation (“ASC 718-10”), which requires all share-based payments to employees and directors, including grants of stock options and restricted stock units, to be recognized in the income statement based on their fair values. Share-based payments that contain performance conditions are recognized when such conditions are probable of being achieved. The Company grants share-based awards to employees in the form of options to purchase the Company’s common stock, the ability to purchase stock at a discounted price under the employee stock purchase plan and restricted stock units. The Company uses the Black-Scholes option pricing model to determine the weighted-average fair value of options granted and determines the intrinsic value of restricted stock units based on the closing price of its common stock on the date of grant. The Company recognizes the compensation expense of share-based awards on a straight-line basis for awards with only service conditions and on an accelerated basis for awards with performance conditions. Compensation expense is recognized over the vesting period of the awards. Stock-based compensation from continuing operations related to share-based awards recognized in the years ended December 31, 2017 , 2016 and 2015 was $31.9 million , $23.8 million and $18.7 million , respectively. At December 31, 2017 , the Company had $41.2 million of total unrecognized compensation expense related to unvested stock options and restricted stock units. Equity Award Plans In May 2007, in conjunction with the Company's initial public offering, the Company adopted its 2007 Stock Option and Incentive Plan (the "2007 Plan"). The 2007 Plan was amended and restated in November 2008, May 2012 and May 2015 to provide for the issuance of additional shares and to amend certain other provisions. Under the 2007 Plan, awards were granted to persons who were, at the time of grant, employees, officers, non-employee directors or key persons (including consultants and prospective employees) of the Company or the Company's subsidiaries. The 2007 Plan provided for the grant of stock options, restricted stock units, stock appreciation rights, deferred stock awards, restricted stock, unrestricted stock, cash-based awards, performance share awards or dividend equivalent rights. Options granted under the 2007 Plan generally vest over a period of four years and expire ten years from the date of grant. In May 2017, the Company adopted the 2017 Stock Option and Incentive Plan (the "2017 Plan"), which has replaced the 2007 Plan as the means by which the Company makes equity and cash awards. Effective May 18, 2017, the 2017 Plan became effective (the "2017 Plan Effective Date") and the Company ceased granting awards from the 2007 Plan. Outstanding awards under the 2007 Plan remain subject to the terms of the 2007 Plan. Under the 2017 Plan, awards may be granted to persons who are, at the time of grant, employees, officers, non-employee directors, consultants, or advisers of the Company or the Company's subsidiaries and affiliates. The 2017 Plan provides for the grant of stock options, restricted stock units, stock appreciation rights, deferred stock awards, restricted stock, unrestricted stock, cash-based awards, performance share awards or dividend equivalent rights. Stock options granted under the 2017 Plan generally vest over a period of four years and expire ten years from the date of grant. Shares of stock subject to awards granted under the 2007 Plan and the 2017 Plan that are forfeited, expire or otherwise terminate without delivery generally become available for future issuance under the 2017 Plan. As of December 31, 2017 , 5.1 million shares remain available for future issuance under the 2017 Plan. Stock Options In the years ended December 31, 2017, 2016 and 2015, the Company awarded 34,500 , 65,000 and 194,500 shares of performance-based incentive stock options, respectively. These stock options were granted under the 2007 and 2017 Plans and vest over a four year period from the grant date with the potential of an accelerated vesting period pursuant to the achievement of certain performance conditions. The determination of the fair value of share-based payment awards utilizing the Black-Scholes model is affected by the stock price and the following assumptions, including expected volatility, expected life of the awards, the risk-free interest rate, and the dividend yield. • Expected volatility measures the amount that a stock price has fluctuated or is expected to fluctuate during a period and is computed over expected terms based upon the historical volatility of the Company's stock. • The expected life of the awards is estimated based on the midpoint scenario, which combines historical exercise data with hypothetical exercise data for outstanding options, as the Company believes this data currently represents the best estimate of the expected life of a new employee option. The Company stratifies its employee population into two groups based upon organizational hierarchy. • The risk-free interest rate assumption is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term on the options. • The dividend yield assumption is based on Company history and expectation of paying no dividends. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Stock-based compensation expense recognized in the financial statements is based on awards that are ultimately expected to vest. If the Company’s actual forfeiture rate is materially different from its estimate, the stock-based compensation expense could be significantly different from what the Company has recorded in the current period. The Company evaluates the assumptions used to value the awards on a quarterly basis and if factors change and different assumptions are utilized, stock-based compensation expense may differ significantly from what has been recorded in the past. If there are any modifications or cancellations of the underlying unvested securities, the Company may be required to accelerate, increase or cancel any remaining unearned stock-based compensation expense. The estimated grant date fair values of the employee stock options were calculated using the Black-Scholes option pricing model, based on the following assumptions: Years Ended December 31, 2017 2016 2015 Risk-free interest rate 1.66% - 1.85% 0.99% - 1.91% 1.16% - 1.75% Expected term (in years) 4.7 - 5.3 5.1 - 5.4 4.9 - 5.3 Dividend yield — — — Expected volatility 38% - 39% 38% - 40% 37% - 38% The weighted average grant date fair value per share of options granted for the years ended December 31, 2017 , 2016 and 2015 was $17.28 , $11.60 and $11.09 , respectively. The following summarizes the activity under the Company’s stock option plans: Number of Options (#) Weighted Average Exercise Price ($) Weighted Average Remaining Contractual Term Aggregate Intrinsic Value ($) (In thousands) Outstanding at December 31, 2016 3,441,303 $ 32.27 Granted 543,045 45.99 Exercised (505,207 ) 27.72 $ 11,846 Canceled (101,921 ) 34.29 Outstanding at December 31, 2017 3,377,220 $ 35.10 7.6 $ 114,505 Vested, December 31, 2017 1,934,398 $ 33.51 7.0 $ 68,654 Vested or expected to vest, December 31, 2017 (1) 3,211,982 $ 34.93 7.6 $ 109,462 (1) Represents total outstanding stock options as of December 31, 2017 , adjusted for the estimated forfeiture. The aggregate intrinsic value of stock options exercised was calculated based on the positive difference between the estimated fair value of the Company’s common stock and the exercise price of the underlying options. The aggregate intrinsic value of options exercised in the years ended December 31, 2016 and 2015 was $4.6 million and $8.6 million , respectively. The aggregate intrinsic value for outstanding awards as of December 31, 2017 was calculated based on the positive difference between the Company’s closing stock price of $69.00 on December 31, 2017 and the exercise price of the underlying options. Employee stock-based compensation from continuing operations related to stock options in the years ended December 31, 2017 , 2016 and 2015 was $11.6 million , $9.9 million and $9.1 million , respectively, and was based on awards ultimately expected to vest. Stock-based compensation from discontinued operations related to stock options was not significant for these periods. At December 31, 2017 , the Company had $15.5 million of total unrecognized compensation expense related to stock options that will be recognized over a weighted average vesting period of 2.4 years. Restricted Stock Units In the years ended December 31, 2017 and 2016 , the Company awarded 436,066 and 592,783 restricted stock units, respectively, to certain employees and non-employee members of the Board of Directors, which included 169,394 and 154,991 restricted stock units, respectively, subject to the achievement of performance conditions (performance-based restricted stock units). For performance-based restricted stock units for which the performance criteria has not yet been achieved as of December 31, 2017 , the Company recognized stock compensation expense of $5.9 million and $2.4 million in 2017 and 2016 , respectively, as it expects a portion of the performance-based restricted stock units granted will be earned based on its evaluation of the performance criteria. An additional $0.5 million and $1.0 million of stock compensation expense was recognized in 2017 and 2016 , respectively, for performance-based restricted stock units for which the performance criteria had been achieved as of the end of these periods. The restricted stock units generally vest annually over a one or three year period from the grant date, except for the performance-based restricted stock units, which follow different vesting patterns. The restricted stock units granted in 2017 have a weighted average fair value of $47.64 per share based on the closing price of the Company’s common stock on the date of grant. The restricted stock units granted during the year ended December 31, 2017 were valued at approximately $20.8 million on their grant date, and the Company is recognizing the compensation expense over the vesting period. Approximately $13.3 million , $10.2 million and $8.1 million of stock-based compensation expense from continuing operations related to the vesting of non-performance based restricted stock units was recognized in the years ended December 31, 2017 , 2016 and 2015 , respectively. Employee stock-based compensation expense from discontinued operations related to the vesting of non-performance based restricted stock was not significant for the three year period ended December 31, 2017. Approximately $25.7 million of the fair value of restricted stock units, including performance-based restricted stock units, remained unrecognized as of December 31, 2017 and will be recognized over a weighted average period of 1.8 years. Under the terms of the awards, the Company will issue shares of common stock on each of the vesting dates. The following table summarizes the status of the Company’s restricted stock units: Number of Shares (#) Weighted Average Fair Value ($) Outstanding at December 31, 2016 962,219 $ 31.14 Granted 436,066 47.64 Vested (386,284 ) 31.79 Forfeited (17,637 ) 33.68 Outstanding at December 31, 2017 994,364 $ 38.08 Employee Stock Purchase Plan The Employee Stock Purchase Plan (“ESPP”) authorizes the issuance of up to a total of 380,000 shares of common stock to participating employees. The Company makes one or more offerings each year to eligible employees to purchase stock under the ESPP. Offering periods begin on the first business day occurring on or after each December 1 and June 1 and end on the last business day occurring on or before the following May 31 and November 30, respectively. Each employee who is a participant in the Company’s ESPP may purchase up to a maximum of 800 shares per offering period or $25,000 worth of common stock, valued at the start of the purchase period, per year by authorizing payroll deductions of up to 10% of his or her base salary. Unless the participating employee withdraws from the offering period, his or her accumulated payroll deductions will be used to purchase common stock. The purchase price for each share purchased is 85% of the lower of (i) the fair market value of the common stock on the first day of the offering period or (ii) the fair market value of the common stock on the last day of the offering period. The Company issued 59,134 shares of common stock in 2017 , 30,949 shares of common stock in 2016 and 22,039 shares of common stock in 2015 to employees participating in the ESPP. The Company recorded approximately $0.6 million , $0.2 million and $0.1 million of stock-based compensation expense related to the ESPP in each of the years ended December 31, 2017 , 2016 and 2015 . Stockholders' Equity Shareholder Rights Plan In November 2008, the Board of Directors of the Company adopted a shareholder rights plan (the "Shareholder Rights Plan”), as set forth in the Shareholder Rights Agreement between the Company and the rights agent, the purpose of which is, among other things, to enhance the ability of the Board of Directors to protect shareholder interests and to ensure that shareholders receive fair treatment in the event any coercive takeover attempt of the Company is made in the future. The Shareholder Rights Plan could make it more difficult for a third party to acquire, or could discourage a third party from acquiring, the Company or a large block of the Company’s common stock. The Shareholder Rights Plan is scheduled to expire in November 2018. In connection with the adoption of the Shareholder Rights Plan, the Board of Directors of the Company declared a dividend distribution of one preferred stock purchase right (a “Right”) for each outstanding share of common stock to stockholders of record as of the close of business on November 15, 2008. In addition, one Right will automatically attach to each share of common stock issued between November 15, 2008 and the distribution date. The Rights currently are not exercisable and are attached to and trade with the outstanding shares of common stock. Under the Shareholder Rights Plan, the Rights become exercisable if a person or group becomes an “acquiring person” by acquiring 15% or more of the outstanding shares of common stock or if a person or group commences a tender offer that would result in that person or group owning 15% or more of the common stock. The Board of Directors, from time to time, can and has taken action to allow certain shareholders to acquire more than 15% of the outstanding shares of common stock under certain conditions. If a person or group becomes an “acquiring person,” each holder of a Right (other than the acquiring person) would be entitled to purchase, at the then-current exercise price, such number of shares of the Company’s preferred stock which are equivalent to shares of common stock having a value of twice the exercise price of the Right. If the Company is acquired in a merger or other business combination transaction after any such event, each holder of a Right would then be entitled to purchase, at the then-current exercise price, shares of the acquiring company’s common stock having a value of twice the exercise price of the Right.

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2017
Defined Contribution Plan [Abstract]
Defined Contribution Plan	Defined Contribution Plan The Insulet 401(k) Retirement Plan (the “401(k) Plan”) is a defined contribution plan in the form of a qualified 401(k) plan in which substantially all employees are eligible to participate upon hire. Eligible employees may elect to contribute 100% of their eligible compensation up to the IRS maximum. The Company has the option of making both matching contributions and discretionary profit-sharing contributions to the 401(k) Plan. Since 2011, the Company has offered a discretionary match of 50% for the first 6% of an employee’s salary that was contributed to the 401(k) Plan. The Company match vests after the employee attains one year of service. The total amount contributed by the Company under the 401(k) Plan in continuing operations was $3.0 million , $1.6 million and $1.6 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Contributions in discontinued operations were not significant during those same periods.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company accounts for income taxes in accordance with ASC 740-10, Income Taxes (“ASC 740-10”) under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Deferred tax assets and liabilities are determined based on differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates that will be in effect in the years in which the differences are expected to reverse. The Company reviews its deferred tax assets for recoverability considering historical profitability, projected future taxable income, and the expected timing of the reversals of existing temporary differences and tax planning strategies. The effect of a change in enacted tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. As of December 31, 2017, the Company had no uncertain tax positions. On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act ("Tax Reform Act"). The legislation significantly changes U.S. tax law by, among other things, lowering corporate income tax rates, implementing a territorial tax system, expanding the tax base and imposing a tax on deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act permanently reduces the U.S. corporate federal income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018. The Company has recognized the impact of the Tax Reform Act in these consolidated financial statements and related disclosures. Staff Accounting Bulletin No. 118 ("SAB 118") provides Companies with guidance on accounting for the impact of the Tax Reform Act. Specifically, SAB 118 provides for a measurement period, not to exceed one year, that begins on the date of enactment of December 22, 2017, and ends when the Company has obtained, prepared, and analyzed information needed to complete accounting requirements. In accordance with SAB 118, the Company recorded provisional amounts reflecting the impact of the Tax Reform Act in these consolidated financial statements and related disclosures. The impact of the remeasurement of the Company’s U.S. deferred tax assets and liabilities to 21% resulted in a tax benefit of approximately $0.3 million consisting of a reduction of the deferred tax assets of $60.5 million offset by a reduction in the valuation allowance of $60.8 million . The Company recorded no tax expense related to the deemed repatriation tax consisting of a reduction in net operating losses in 2017 of $0.8 million offset by a reduction in the valuation allowance of the $0.8 million . The impact of the deemed repatriation tax computation is still open due to finalization of the earnings and profits of the Company's foreign subsidiaries, as well as the Company’s evaluation of certain elections and guidance. The Company files federal, state and foreign tax returns. These returns are generally open to examination by the relevant tax authorities from two to four years from the date they are filed or, in certain circumstances, from the end of the accounting period. The tax filings relating to the Company's federal and state tax returns are currently open to examination for tax years 2014 through 2016 and 2013 through 2016, respectively. In addition, the Company has generated tax losses since its inception in 2000. These years may be subject to examination if the losses are carried forward and utilized in future years. At December 31, 2017 and 2016 , the Company provided a full valuation allowance against its domestic net deferred tax asset as, in the judgment of the Company, it is not more likely than not that the future tax benefit will be realized. In addition, the Company has a net deferred tax asset in foreign jurisdictions where no valuation allowance is recorded as, in the judgment of the Company, it is more likely than not that the future tax benefit will be realized. Income tax expense from continuing operations consists of the following: Years Ended December 31, (in thousands) 2017 2016 2015 Current: Federal $ — $ — $ — State 151 52 72 Non-U.S. 603 539 321 Total current expense 754 591 393 Deferred: Federal (347 ) — — State 91 — — Non-U.S. (241 ) (199 ) (181 ) Total deferred expense (497 ) (199 ) (181 ) Total income tax expense $ 257 $ 392 $ 212 Income tax expense from discontinued operations was $0.4 million for the year ended December 31, 2016 and was primarily generated from federal deferred taxes. Income tax expense from discontinued operations was not significant for the year ended December 31, 2015. The following table reconciles the federal statutory income rate to the Company's effective income tax rate: Year Ended December 31, 2017 2016 2015 Tax at U.S. statutory rate 34.00 % 34.00 % 34.00 % Changes from statutory rate: State taxes, net of federal benefit 10.21 (10.86 ) 3.06 Tax credits 13.28 0.03 1.51 Permanent items (0.55 ) (11.03 ) (2.09 ) Change in enacted rates 0.98 — — Change in valuation allowance (57.91 ) (13.45 ) (37.11 ) Other (0.98 ) (0.15 ) 0.28 Effective income tax rate (0.97 )% (1.46 )% (0.35 )% Pre-tax income attributable to the Company's operations located outside the U.S. was approximately $1.1 million , $0.8 million and $0.3 million for 2017 , 2016 and 2015 , respectively. In general, it is the Company's practice and intention to reinvest the earnings of its non-U.S. subsidiaries in those operations. As of December 31, 2017 , the Company has chosen to indefinitely reinvest approximately $6.4 million of earnings of certain of its non-U.S. subsidiaries. To the extent the Company repatriates its foreign earnings, certain withholding taxes and state taxes may apply. No provision has been recorded for taxes that could be incurred upon repatriation. The deferred tax liability related to repatriation of these earnings would not be material to the company's consolidated financial statements. Significant components of the Company’s deferred tax assets (liabilities) consists of the following: Year Ended December 31, (in thousands) 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 129,184 $ 169,203 Start up expenditures 462 929 Tax credits 12,705 8,007 Provision for bad debts 824 1,330 Depreciation and amortization 3,068 6,368 Capital loss carryforwards 12,850 18,961 Stock-based compensation 9,799 10,359 Other 4,449 4,701 Total deferred tax assets $ 173,341 $ 219,858 Deferred tax liabilities: Prepaid assets $ (1,326 ) $ (1,173 ) Amortization of acquired intangibles (5 ) (33 ) Amortization of debt discount (43,083 ) (25,977 ) Goodwill (633 ) (855 ) Other (259 ) (313 ) Total deferred tax liabilities $ (45,306 ) $ (28,351 ) Valuation allowance $ (127,927 ) $ (191,922 ) Net deferred tax liabilities $ 108 $ (415 ) The Company has recorded a deferred tax liability related to the tax basis in acquired goodwill that is not amortized for financial reporting purposes. The deferred tax liability will only reverse at the time of further impairment of the goodwill. Due to the uncertain timing of this reversal, the temporary difference cannot be considered as a source of future taxable income for purposes of determining a valuation allowance. Therefore, the deferred tax liability cannot be used to offset the deferred tax asset related to the net operating loss carryforward for tax purposes. The Tax Reform Act limits certain deductions and these limitations may impact the value of existing deferred tax assets. The Company will continue to review the impact of these limitations as regulatory guidance is issued. A valuation allowance is required to reduce the deferred tax assets reported if, based on the weight of the evidence, it is more likely than not that some portion or all of the U.S. deferred tax assets will not be realized. After consideration of the available evidence, both positive and negative, the Company has determined that a $127.9 million valuation allowance at December 31, 2017 is necessary to reduce the deferred tax assets to the amount that will more likely than not be realized. The Company provided a valuation allowance for the full amount of its domestic net deferred tax asset for the years ended December 31, 2017 and 2016 because it is not more likely than not that the future tax benefit will be realized. In the year ended December 31, 2017 , the Company’s valuation allowance decreased to $127.9 million from the balance at December 31, 2016 of $191.9 million . The change in the valuation allowance is primarily attributable to the reduction in the U.S. federal tax rate from 34% to 21% as a result of the 2017 Tax Reform Act, which had an impact of reducing the valuation allowance by approximately $60.8 million . Additional movement in the valuation allowance from December 31, 2016 to December 31, 2017 is comprised of an increase of approximately $15.6 million to offset current year net deferred tax asset and liability changes, a decrease of approximately $42.6 million to offset the net deferred tax liability related to the debt discount and deferred financing costs related to the Company’s 1.375% Notes issued during the year ended December 31, 2017, and an increase of approximately $23.8 million increase related to the adoption of ASU 2016-09 related to accounting for stock-based compensation. At December 31, 2017 , the Company had approximately $543.6 million , $250.6 million and $12.7 million of gross federal net operating loss carryforwards, state net operating loss carryforwards and research and development and other tax credits, respectively. If not utilized, these federal carryforwards will begin to expire in 2020 and will continue to expire through 2037, and the state carryforwards will continue to expire through 2037. At December 31, 2016, the Company had approximately $535.7 million , $216.2 million and $8.0 million of federal net operating loss carryforwards, state net operating loss carryforwards and research and development and other tax credits, respectively from continuing operations. The utilization of such net operating loss carryforwards and the realization of tax benefits in future years depends predominantly upon the Company's ability to generate taxable income. Under the provisions of the Internal Revenue Code, certain substantial changes in the Company's ownership may result in a limitation on the amount of net operating loss carryforwards which may be used in future years whereby there would be a yearly limitation placed on the amount of net operating loss available for use in future years. Additionally, it is probable that a portion of the research and development tax credit carryforward may not be available to offset future income. As a result of certain realization requirements of ASC 718, the table of deferred tax assets and liabilities does not include certain deferred tax assets as of December 31, 2016 that arose directly from tax deductions related to equity compensation greater than compensation recognized for financial reporting. Upon adoption of ASU 2016-09 on January 1, 2017, the Company recorded $23.8 million of deferred tax assets, less a full valuation allowance related to these amounts.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2017
Disclosure Potential Common Shares Excluded From Computation Of Diluted Net Loss Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding for the period, excluding unvested restricted common shares. Diluted net loss per share is computed using the weighted average number of common shares outstanding and, when dilutive, potential common share equivalents from options, restricted stock units and warrants (using the treasury-stock method), and potential common shares from convertible securities (using the if-converted method). Because the Company reported a net loss for the years ended December 31, 2017 , 2016 and 2015 , all potential dilutive common shares have been excluded from the computation of the diluted net loss per share for all periods presented, as the effect would have been anti-dilutive. Potential dilutive common share equivalents consist of the following: Years Ended December 31, 2017 2016 2015 1.375% Convertible Senior Notes 4,319,429 — — 2.00% Convertible Senior Notes 78,783 1,442,433 4,327,257 1.25% Convertible Senior Notes 5,910,954 5,910,954 — Unvested restricted stock units 994,364 962,219 811,965 Outstanding stock options 3,377,220 3,441,303 2,999,199 Total dilutive common shares 14,680,750 11,756,909 8,138,421

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting As further described in Note 2, the Company has concluded that it operates as one segment. Worldwide revenue for the Company's products is categorized as follows: Years Ended December 31, (in thousands) 2017 2016 2015 U.S. Omnipod $ 271,597 $ 229,785 $ 189,604 International Omnipod 119,953 71,889 40,339 Drug Delivery 72,218 65,315 33,950 Total $ 463,768 $ 366,989 $ 263,893 Geographic information about revenue, based on the region of the customer's shipping location, is as follows: Years Ended December 31, (in thousands) 2017 2016 2015 United States $ 343,815 $ 295,100 $ 223,554 All other 119,953 71,889 40,339 Total $ 463,768 $ 366,989 $ 263,893 Geographic information about long-lived assets, net, excluding goodwill and other intangible assets is as follows: (in thousands) December 31, 2017 December 31, 2016 United States $ 89,404 $ 19,341 China 18,217 25,431 Other 434 197 Total $ 108,055 $ 44,969

Business Combination

Business Combination	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Business Combination	Business Combination On July 7, 2015, the Company executed an asset purchase agreement with GlaxoSmithKline ("GSK") whereby the Company acquired GSK's assets associated with the Canadian distribution of the Company's products. The acquisition was accounted for as a business combination. With the acquisition, the Company assumed all distribution, sales, marketing, training and support activities for the Omnipod System in Canada through its wholly-owned subsidiary, Insulet Canada Corporation. The acquisition allowed the Company to establish a local presence in Canada that enabled it to engage directly with healthcare providers and Omnipod users. The aggregate purchase price of approximately $4.7 million consisted of cash paid at closing and was allocated to the fair value of assets acquired and liabilities assumed as follows: (in thousands) Goodwill $ 2,403 Contractual relationships 2,100 Inventory step-up 230 Assumed liabilities (18 ) $ 4,715

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations In February 2016, the Company sold Neighborhood Diabetes to Liberty Medical for approximately $6.2 million in cash, which included $1.2 million of closing adjustments finalized in June 2016 and paid by Liberty Medical. The results of operations, assets, and liabilities of Neighborhood Diabetes, are classified as discontinued operations for all periods presented, except for certain corporate overhead costs which remain in continuing operations. In connection with the 2016 disposition, the Company entered into a transition services agreement pursuant to which various services were provided to Liberty Medical on an interim transitional basis. Total expenses incurred for such transition services were $0.9 million for the year ended December 31, 2016. Following the disposition, the Company entered into a distribution agreement with the Neighborhood Diabetes subsidiary of Liberty Medical to continue to act as a distributor for the Company's products. Omnipod sales transacted through Neighborhood Diabetes prior to the divestiture that were previously eliminated in consolidation were $0.3 million and $2.8 million for the years ended December 31, 2016 and 2015 , respectively. These amounts were historically reported in the Neighborhood Diabetes revenue results and are being presented based on current market terms of products sold to the Neighborhood Diabetes subsidiary of Liberty Medical. Post divestiture, Omnipod System sales to the Neighborhood Diabetes subsidiary of Liberty Medical were $0.4 million for the year ended December 31, 2016. The following is a summary of the operating results of Neighborhood Diabetes included in discontinued operations for the year ended December 31, 2016 and 2015 : Years Ended December 31, (In thousands) 2016 2015 Discontinued operations: Revenue (1) $ 7,730 $ 60,332 Cost of revenue 5,468 45,449 Gross profit 2,262 14,883 Operating expenses: Sales and marketing 1,542 9,945 General and administrative (2) (3) 1,853 16,967 Total operating expenses 3,395 26,912 Operating loss (1,133 ) (12,029 ) Interest and other income (expense), net (128 ) 190 Loss from discontinued operations before taxes (1,261 ) (11,839 ) Income tax expense 408 79 Net loss from discontinued operations $ (1,669 ) $ (11,918 ) (1) Revenue for the year ended December 31, 2016 includes revenue from operations of Neighborhood Diabetes through the date of sale in February 2016. (2) Included in general and administration expenses for the year ended December 31, 2015 was a charge of $9.1 million related to the impairment of Neighborhood Diabetes asset group. (3) Included in general and administration expenses for the year ended December 31, 2015 was $0.5 million of stock-based compensation expense from discontinued operations related to share-based awards. Stock-based compensation expense from discontinued operations related to share-based awards was not significant for the year ended December 31, 2016. Depreciation and amortization expense included in discontinued operations was $0.0 million , $0.1 million , and $3.3 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. There were no assets or liabilities presented as discontinued operations as of December 31, 2017 or December 31, 2016. Net operating cash flows used in discontinued operations in the years ended December 31, 2017 , 2016 and 2015 were $0.0 million , $2.0 million , and $3.2 million , respectively.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Data (Unaudited) [Abstract]
Quarterly Data (Unaudited)	Quarterly Data (Unaudited) 2017 Quarters Ended December 31 September 30 June 30 March 31 (In thousands, except per share data) Revenue $ 130,524 $ 121,775 $ 109,756 $ 101,713 Gross profit 79,508 73,624 64,639 59,398 Operating (loss) income (768 ) 2,047 (3,358 ) (5,308 ) Net loss $ (6,860 ) $ (2,227 ) $ (7,767 ) $ (9,977 ) Net loss per share $ (0.12 ) $ (0.04 ) $ (0.13 ) $ (0.17 ) 2016 Quarters Ended December 31 (1) September 30 June 30 March 31 (In thousands, except per share data) Revenue $ 103,575 $ 94,871 $ 87,330 $ 81,213 Gross profit 60,937 55,641 50,457 44,051 Operating (loss) income (4,135 ) 2,418 (1,288 ) (7,699 ) Net loss from continuing operations, net of taxes (9,153 ) (3,017 ) (4,351 ) (10,689 ) Income (loss) from discontinued operations, net of taxes 34 (64 ) 153 (1,792 ) Net loss $ (9,119 ) $ (3,081 ) $ (4,198 ) $ (12,481 ) Net loss per share from continuing operations $ (0.16 ) $ (0.05 ) $ (0.08 ) $ (0.19 ) Net loss per share from discontinued operations $ — $ — $ — $ (0.03 ) (1) Included in net loss from continuing operations for the fourth quarter of 2016 was a charge of $6.1 million related to in-process internally developed software.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS The following table sets forth activities in the Company's accounts receivable reserve and deferred tax valuation allowance accounts: Description Balance at Beginning of Period Additions Charged to Costs and Expenses Deductions Balance at End of Period (In thousands) Year Ended December 31, 2017 Allowance for doubtful accounts $ 2,911 $ 1,923 $ 2,293 $ 2,541 Deferred tax valuation allowance $ 191,922 $ 14,232 $ 78,227 $ 127,927 Year Ended December 31, 2016 Allowance for doubtful accounts (1) $ 4,454 $ 2,069 $ 3,612 $ 2,911 Deferred tax valuation allowance (1) $ 193,405 $ 7,599 $ 9,082 $ 191,922 Year Ended December 31, 2015 Allowance for doubtful accounts (1) $ 5,837 $ 1,184 $ 2,567 $ 4,454 Deferred tax valuation allowance (1) $ 165,020 $ 28,418 $ 33 $ 193,405 (1) Includes the amount classified as discontinued operations on the consolidated balance sheet and related activity.

Summary of Significant Accoun32

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Use of Estimates in Preparation of Financial Statements	Use of Estimates in Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States ("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. The most significant estimates used in these financial statements include the valuation of stock-based compensation expense; the fair value of intangible assets acquired in businesses combinations; the valuation of inventory; the valuation of deferred revenue; the calculation of gains and losses, if any, on the retirement or conversion of convertible debt; the estimated useful lives of property and equipment and intangible assets; the amount of internal use software development costs that qualify for capitalization; the valuation allowance related to deferred income taxes, the estimated amount, if any, of accrued contingent liabilities as well as warranty and doubtful accounts allowance reserve calculations. Actual results may differ from those estimates.
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, primarily related to internal-use software intangible assets, have been made to prior period amounts to conform to the current period financial statement presentation
Foreign Currency Translation	Foreign Currency Translation For foreign operations, asset and liability accounts are translated at exchange rates as of the balance sheet date; income and expenses are translated using weighted average exchange rates for the reporting period. Resulting translation adjustments are reported in accumulated other comprehensive loss, a separate component of stockholders' equity. Gains and losses arising from transactions and translation of period-end balances denominated in currencies other than the functional currency, primarily the Canadian dollar, are included in interest and other income (expense), net, and were not material for fiscal years 2017 , 2016 and 2015 .
Cash and Cash Equivalents	Cash and Cash Equivalents For the purpose of the financial statement classification, the Company considers all highly-liquid investment instruments with original maturities of 90 days or less, when purchased, to be cash equivalents. Cash equivalents include money market mutual funds, corporate bonds, and certificates of deposit which are carried at cost which approximates their fair value. Included in the Company's cash and cash equivalents are restricted cash amounts set aside for collateral on outstanding letters of credit related to lease obligations totaling $0.5 million as of December 31, 2017 and $1.2 million as of December 31, 2016 .
Investments in Marketable Securities	Investments in Marketable Securities Short-term and long-term investment securities consist of available-for-sale marketable securities and are carried at fair value with unrealized gains or losses included as a component of other comprehensive loss in stockholders' equity. Investments, exclusive of cash equivalents, with a stated maturity date of more than one year from the balance sheet date and that are not expected to be used in current operations, are classified as long-term investments. Short-term and long-term investments include U.S. government and agency bonds, corporate bonds, and certificates of deposit. The Company reviews investments for other-than-temporary impairment when the fair value of an investment is less than its amortized cost. If an available-for-sale security is other than temporarily impaired, the loss is charged to earnings.
Property and Equipment	Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful life of the respective assets. Leasehold improvements are amortized over their useful life or the life of the lease, whichever is shorter. Assets acquired under capital leases are amortized in accordance with the respective class of owned assets and the amortization is included with depreciation expense. Maintenance and repair costs are expensed as incurred.
Business Combinations	Business Combinations The Company recognizes the assets and liabilities assumed in business combinations on the basis of their fair values at the date of acquisition. The Company assesses the fair value of assets, including intangible assets, using a variety of methods and each asset is measured at fair value from the perspective of a market participant. The method used to estimate the fair values of intangible assets incorporates significant assumptions regarding the estimates a market participant would make in order to evaluate an asset, including a market participant’s use of the asset and the appropriate discount rates for a market participant. Assets recorded from the perspective of a market participant that are determined to not have economic use for the Company are expensed immediately. Any excess purchase price over the fair value of the net tangible and intangible assets acquired is allocated to goodwill. Transaction costs and restructuring costs associated with a business combination are expensed as incurred.
Segment Reporting	Segment Reporting Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated on a regular basis by the chief operating decision-maker ("CODM") in deciding how to allocate resources to an individual segment and in assessing performance of the segment. The Company has concluded that its Chief Executive Officer is the CODM as he is the ultimate decision maker for key operating decisions, determining the allocation of resources and assessing the financial performance of the Company. These decisions, allocations and assessments are performed by the CODM using consolidated financial information. Consolidated financial information is utilized by the CODM as the Company’s current product offering primarily consists of the Omnipod System and drug delivery. The Company’s products are relatively consistent and manufacturing is centralized and consistent across product offerings. Based on these factors, key operating decisions and resource allocations are made by the CODM using consolidated financial data and as such the Company has concluded that it operates as one segment.
Goodwill	Goodwill Goodwill represents the excess of the cost of acquired businesses over the fair value of identifiable net assets acquired. The Company follows the provisions of Financial Accounting Standards Board ("FASB") ASC 350-20, Intangibles - Goodwill and Other (“ASC 350-20”) whereby the Company performs an assessment of its goodwill for impairment on at least an annual basis or whenever events or changes in circumstances indicate there might be impairment. The Company's annual impairment test date is October 1st. Goodwill is evaluated for impairment at the reporting unit level. As the Company operates in one segment, the Company has considered whether that segment contains multiple components which represent separate reporting units. The Company has concluded that it has a single reporting unit. In reaching this conclusion, the Company considered how components of the business are managed, whether discrete financial information at the component level is reviewed on a regular basis by segment management and whether components may be aggregated based on economic similarity. In performing that annual goodwill test, the Company utilizes the two-step approach as currently prescribed by ASC 350-20. The first step compares the carrying value of the reporting unit to its fair value. If the reporting unit’s carrying value exceeds its fair value, the Company would perform the second step and record an impairment loss to the extent that the carrying value of the reporting unit's goodwill exceeds its implied fair value. There were no impairments of goodwill during the years ended December 31, 2017 , 2016 or 2015 .
Revenue Recognition	Revenue Recognition The Company generates the majority of its revenue from sales of its Omnipod System directly to patients and through third-party distributors. Revenue recognition requires that persuasive evidence of a sales arrangement exists, delivery of goods occurs through transfer of title and risk and rewards of ownership, the selling price is fixed or determinable and collectability is reasonably assured. With respect to these criteria: • The evidence of an arrangement generally consists of a physician order form, a patient information form and, if applicable, third-party insurance approval for sales directly to patients or a purchase order for sales to a third-party distributor. • Revenue is recognized when title and risk and rewards of ownership have transferred to the customer. • The selling prices for all sales are fixed and agreed with the patient or third-party distributor and, if applicable, the patient’s third-party insurance provider(s) prior to shipment and are based on established list prices or, in the case of certain third-party insurers, contractually agreed upon prices. Provisions for discounts, rebates and other adjustments to customers are established as a reduction to revenue in the same period the related sales are recorded. The Company offers a 45 -day right of return for sales of its Omnipod System in the United States, and a 90 -day right of return for sales of its Omnipod System in Canada to new patients and defers revenue to reflect estimated sales returns in the same period that the related product sales are recorded. Returns are estimated through a comparison of the Company’s historical return data to its related sales. Historical rates of return are adjusted for known or expected changes in the marketplace when appropriate. When doubt exists about reasonable assuredness of collectability from specific customers, the Company defers revenue from sales of products to those customers until payment is received.
Collaborative Arrangements	Collaborative Arrangements The Company enters into collaborative arrangements for ongoing initiatives to develop products. Although the Company does not consider any individual alliance to be material, the following more notable alliances are described below. Eli Lilly and Concentrated insulins : In May 2013, the Company entered into an agreement with Eli Lilly and Company (Eli Lilly) to develop a new version of the Omnipod System specifically designed to deliver Humulin ® R U-500 insulin, a concentrated form of insulin used by people with highly insulin resistant Type 2 diabetes. In January 2016, the Company entered into a development agreement with Eli Lilly to develop a new version of Insulet's Omnipod tubeless insulin delivery system, specifically designed to deliver Lilly's Humalog ® 200 units/mL insulin, a concentrated form of insulin used by higher insulin-requiring patients with diabetes that provides the same dose of insulin in half the volume of Lilly's Humalog ® U-100 insulin. Under the terms of these arrangements, the parties share the responsibility of the permissible costs that are incurred. Any amounts incurred in excess of the permissible shared costs that are the responsibility of one party becomes due and payable by the other party. Consideration received and payments made by the Company under the terms of the arrangements are recorded within research and development expense.
Shipping and Handling Costs	Shipping and Handling Costs The Company does not typically charge its customers for shipping and handling costs associated with shipping its product to its customers unless non-standard shipping and handling services are requested. These shipping and handling costs are included in general and administrative expenses
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents, short-term and long-term investments in marketable securities and accounts receivable. The Company maintains the majority of its cash and short-term and long-term investments with one financial institution. Accounts are partially insured up to various amounts mandated by the Federal Deposit Insurance Corporation or by the foreign country where the account is held. The Company purchases Omnipod Systems from Flex Ltd., its single source supplier.
Recent Accounting Pronouncements	Recently Adopted Accounting Standards During 2017, the Company retrospectively adopted Accounting Standards Update ("ASU") 2016-19, Technical Corrections and Improvements, which included clarification that the license of internal-use software shall be accounted for as the acquisition of an intangible asset. As a result of adoption, the Company reclassified $4.1 million of gross internal-use software costs, net of accumulated amortization of $2.6 million , from property and equipment to other intangible assets as of December 31, 2016. Effective January 1, 2017, the Company adopted ASU 2015-11, Simplifying the Measurement of Inventory, which requires entities to measure most inventory at the lower of cost and net realizable value. The adoption of this guidance did not have a material impact on the consolidated financial statements. Effective January 1, 2017, the Company adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09") using the modified retrospective method. ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The adoption of ASU 2016-09 resulted in the Company increasing its deferred tax assets by approximately $23.8 million , which was offset by a full valuation allowance. The adoption of the standard did not have a material impact on the Company's consolidated financial statements. Effective January 1, 2017, the Company adopted ASU 2016-18, Restricted Cash (a consensus of the Emerging Issues Task Force) ("ASU 2016-18") using the retrospective transition method. ASU 2016-18 requires the statement of cash flows to show the changes in the total of cash, cash equivalents, and restricted cash. There was no significant impact on the statement of cash flows upon the adoption of ASU 2016-18. Accounting Pronouncements Issued and Not Yet Adopted as of December 31, 2017 In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09"). ASU 2014-09 and its related amendments (collectively referred to as ASC 606) requires that an entity recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Under this guidance, an entity makes additional estimates regarding performance conditions and the allocation of variable consideration and must evaluate whether revenue derived from a contract should be recognized at a point in time or over time. The Company adopted the standard as of the required effective date of January 1, 2018 using the modified retrospective method. Under this method, the new guidance was applied to contracts that were not yet completed as of January 1, 2018 with the cumulative effect of initially applying the guidance recognized through accumulated deficit as the date of initial application. In addition to the enhanced footnote disclosures related to customer contracts, the Company anticipates that the most significant impact of the new standard will relate to the timing of revenue recognition relative to a portion of its drug delivery product line, the deferral and amortization of contract acquisition costs such as commissions and a material right granted to the Company's European distributor in 2010. The quantitative ranges provided below are estimates of the expected effects of the Company’s adoption of ASC 606 as of the time of preparation of this Annual Report on Form 10-K. The anticipated accounting impacts described below will have no impact on cash flows. i. Drug Delivery Revenue. The adoption of ASC 606 will accelerate the timing of revenue recognition relative to a portion of the Company's drug delivery product line whereby revenue will be recognized as the product is produced pursuant to the customer’s firm purchase commitments as the Company has an enforceable right to payment for performance completed to date and the inventory has no alternative use to the Company. This guidance is in contrast to legacy accounting guidance whereby revenue is recognized when the product is shipped to the customer. Upon the adoption of ASC 606 on January 1, 2018, the Company expects to record a contract asset on its consolidated balance sheet of approximately $4 million to $6 million to reflect revenue that would have been recognized upon shipment of the product in 2018 under ASC 605 but will not be under ASC 606 as it would have been recognized in 2017 as the product was produced. The impact on the Company's drug delivery revenue in 2018 and forward will depend on the timing of drug delivery inventory production levels. ii. Material Right. The adoption of ASC 606 will require the Company to record a contract liability on January 1, 2018 of approximately $1 million to $3 million associated with a volume-based pricing discount granted to the Company's European distributor at the outset of the distribution contract in 2010. The contract liability will be classified as deferred revenue and will be recognized as revenue through the completion of the distributor contract during the first half of 2018. iii. Contract Acquisition Costs. The adoption of ASC 606 will impact the treatment of contract acquisition costs, such as commissions, which will be capitalized and amortized over the expected period of benefit. Upon adoption, the Company expects to increase its current and other assets by approximately $18 million to $20 million for the net value of cumulative commissions paid prior to adoption less amortization to date. The new guidance will likely have an accretive impact to the Company's earnings in 2018 as the Company continues to increase its customer base. The deferred tax assets and liabilities resulting from these adjustments will be substantially offset by an associated adjustment to the Company valuation allowance. Therefore, as the Company currently maintains a full valuation allowance against its domestic net deferred tax assets, the Company does not expect the adoption of ACS 606 to have a significant impact on its deferred tax balances or income tax expense in 2018. Effective January 1, 2018, the Company adopted ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"). ASU 2016-01 changes the current GAAP model for the accounting of equity investments, whereby equity investments with readily determinable fair value will be carried at fair value with changes reported in net income (loss) as opposed to other comprehensive income (loss). The classification and measurement guidance was effective January 1, 2018 for the Company. As the Company held no available for sale equity investments on December 31, 2017, there was no impact on the consolidated financial statements upon the adoption of ASU 2016-01. Effective January 1, 2018, the Company adopted ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) ("ASU 2016-15"). ASU 2016-15 clarifies how entities should classify certain cash receipts and cash payments on the statement of cash flows. The guidance also clarifies how the predominance principle should be applied when cash receipts and cash payments have aspects of more than one class of cash flows. The Company does not expect that the adoption of this guidance will have an impact on the consolidated statement of cash flows. Effective January 1, 2018, the Company adopted ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting ("ASU 2017-09"). ASU 2017-09 specifies the types of changes to the terms or conditions of a share-based payment award that require an entity to apply modification accounting in accordance with Topic 718. The new standard is effective for the Company on January 1, 2018 and early adoption is permitted. The adoption of ASU 2017-09 did not have an impact on the Company's consolidated financial statements. Effective January 1, 2018, the Company adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory ("ASU 2016-16"). ASU 2016-16 requires than an entity recognized the income tax effects of an intra-entity transfer of an asset, other than inventory, when the transfer occurs as opposed to when the asset is sold to a third party. The Company does not expect that the adoption of this guidance will have a material impact on the consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12"). ASU 2017-12 updates the current hedge accounting guidance with the objective of improving the financial reporting of hedging activities by better portraying the economic results of an entity's risk management activities in its financial statements. The new guidance is effective for the Company on January 1, 2019 and early adoption is permitted. The Company is currently evaluating the impact of ASU 2017-12 on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases ("ASU 2016-02"). ASU 2016-02 requires lessees to recognize the assets and liabilities on their balance sheet for the rights and obligations created by most leases and continue to recognize expenses on their income statements over the lease term. The new guidance will also require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for the Company on January 1, 2019 and is expected to be applicable to all leases in place as of the beginning of the earliest reporting period. The Company does not expect to early-adopt the guidance. While the Company is currently evaluating the impact of ASU 2016-02, the Company currently expects that the new guidance will require an increase in the Company's long-lived assets and a corresponding increase to long-term obligations associated with leased office and warehouse space. In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating "Step 2" from the goodwill impairment test, which requires an entity to calculate the implied fair value of goodwill to measure a goodwill impairment charge, and alternatively, requires an entity to measure the impairment of goodwill assigned to a reporting unit as the amount by which the carrying value of the assets and liabilities of the reporting unit, including goodwill, exceeds the reporting unit's fair value. The guidance is effective for annual reporting periods beginning after December 15, 2019, and interim periods within those years. Early adoption is permitted for all entities. The Company is currently evaluating the impact of ASU 2017-04 but does not expect it to be material to the consolidated financial statements.
Fair Value of Financial Instruments	The Company applies ASC 820, Fair Value Measurements and Disclosures (“ASC 820”) related to the fair value measurement of certain of its assets and liabilities. ASC 820 defines fair value as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions. When estimating fair value, depending on the nature and complexity of the asset or liability, the Company may use one or all of the following approaches: • Market approach, which is based on market prices and other information from market transactions involving identical or comparable assets or liabilities. • Cost approach, which is based on the cost to acquire or construct comparable assets less an allowance for functional and/or economic obsolescence. • Income approach, which is based on the present value of the future stream of net cash flows. To measure fair value, the Company uses the following fair value hierarchy based on three levels of inputs, as described in ASC 820, of which the first two are considered observable and the last unobservable: 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 in which there is little or no market data available, which require the reporting entity to develop its own assumptions Certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable, accrued expenses and other liabilities are carried at cost, which approximates their fair value because of the short-term maturity of these financial instruments.
Accounts Receivable, Net	Accounts receivable consist of amounts due from third-party payors, patients, and third-party distributors. The Company records an allowance for doubtful accounts at the time potential collection risk is identified. The Company estimates its allowance based on historical experience, assessment of specific risk, discussions with individual customers or various assumptions and estimates that are believed to be reasonable under the circumstances. The Company believes the reserve is adequate to mitigate current collection risk.
Inventories, Net	Inventories are held at the lower of cost or market, determined under the first-in, first-out method, and include the costs of material, labor and overhead. Inventory has been recorded at cost, or net realizable value as appropriate, as of December 31, 2017 and 2016 . The Company reviews inventories for net realizable value based on quantities on hand and expectations of future use. Work in process is calculated based upon a buildup in the stage of completion using estimated labor inputs for each stage in production.
Other Intangible Assets	The Company’s finite-lived intangible assets are stated at cost less accumulated amortization. The Company assesses its intangible and other long-lived assets for impairment whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. The Company recognizes an impairment loss for intangibles and other finite-lived assets if the carrying amount of a long-lived asset is not recoverable based on its undiscounted future cash flows. Any such impairment loss is measured as the difference between the carrying amount and the fair value of the asset. During 2016, the Company restructured its plan for an internally developed ERP system in order to leverage current third-party software available and scale conversion based on the Company's evolving ERP needs. As a result, the Company recorded a charge of $6.1 million , included in general and administrative expenses, related to this in-process internally developed software.
Product Warranty	Product Warranty Costs The Company provides a four -year warranty on its PDMs sold in the United States and a five -year warranty on its PDMs sold in Canada and may replace any Omnipod that does 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. Warranty expense is recorded in cost of goods sold on the statement of operations. Cost to service the claims reflects the current product cost. As these estimates are based on historical experience, and the Company continues to introduce new products and versions, the Company also considers the anticipated performance of the product over its warranty period in estimating warranty reserves.
Stock-Based Compensation	The Company accounts for stock-based compensation under the provisions of ASC 718-10, Compensation — Stock Compensation (“ASC 718-10”), which requires all share-based payments to employees and directors, including grants of stock options and restricted stock units, to be recognized in the income statement based on their fair values. Share-based payments that contain performance conditions are recognized when such conditions are probable of being achieved.
Income Taxes	The Company accounts for income taxes in accordance with ASC 740-10, Income Taxes (“ASC 740-10”) under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Deferred tax assets and liabilities are determined based on differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates that will be in effect in the years in which the differences are expected to reverse. The Company reviews its deferred tax assets for recoverability considering historical profitability, projected future taxable income, and the expected timing of the reversals of existing temporary differences and tax planning strategies. The effect of a change in enacted tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. As of December 31, 2017, the Company had no uncertain tax positions. On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act ("Tax Reform Act"). The legislation significantly changes U.S. tax law by, among other things, lowering corporate income tax rates, implementing a territorial tax system, expanding the tax base and imposing a tax on deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act permanently reduces the U.S. corporate federal income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018. The Company has recognized the impact of the Tax Reform Act in these consolidated financial statements and related disclosures. Staff Accounting Bulletin No. 118 ("SAB 118") provides Companies with guidance on accounting for the impact of the Tax Reform Act. Specifically, SAB 118 provides for a measurement period, not to exceed one year, that begins on the date of enactment of December 22, 2017, and ends when the Company has obtained, prepared, and analyzed information needed to complete accounting requirements. In accordance with SAB 118, the Company recorded provisional amounts reflecting the impact of the Tax Reform Act in these consolidated financial statements and related disclosures. The impact of the remeasurement of the Company’s U.S. deferred tax assets and liabilities to 21% resulted in a tax benefit of approximately $0.3 million consisting of a reduction of the deferred tax assets of $60.5 million offset by a reduction in the valuation allowance of $60.8 million . The Company recorded no tax expense related to the deemed repatriation tax consisting of a reduction in net operating losses in 2017 of $0.8 million offset by a reduction in the valuation allowance of the $0.8 million . The impact of the deemed repatriation tax computation is still open due to finalization of the earnings and profits of the Company's foreign subsidiaries, as well as the Company’s evaluation of certain elections and guidance. The Company files federal, state and foreign tax returns. These returns are generally open to examination by the relevant tax authorities from two to four years from the date they are filed or, in certain circumstances, from the end of the accounting period. The tax filings relating to the Company's federal and state tax returns are currently open to examination for tax years 2014 through 2016 and 2013 through 2016, respectively. In addition, the Company has generated tax losses since its inception in 2000. These years may be subject to examination if the losses are carried forward and utilized in future years. At December 31, 2017 and 2016 , the Company provided a full valuation allowance against its domestic net deferred tax asset as, in the judgment of the Company, it is not more likely than not that the future tax benefit will be realized. In addition, the Company has a net deferred tax asset in foreign jurisdictions where no valuation allowance is recorded as, in the judgment of the Company, it is more likely than not that the future tax benefit will be realized.

Summary of Significant Accoun33

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Change in Carrying Amount of Goodwill From Continuing Operations	The following table presents the change in carrying amount of goodwill during the period indicated: Years Ended December 31, (In thousands) 2017 2016 Goodwill: Beginning balance $ 39,677 $ 39,607 Foreign currency adjustment 163 70 Ending balance $ 39,840 $ 39,677
Schedule of Customer Concentration Risks	Revenue for customers comprising more than 10% of total revenue were as follows: Twelve Months Ended December 31, 2017 2016 2015 Amgen, Inc. 15% 17% 10% Ypsomed Distribution AG 22% 16% 12% RGH Enterprises, Inc. 11% 10% 13% Customers that represented greater than 10% of gross accounts receivable as of December 31, 2017 , and 2016 were as follows: As of December 31, 2017 December 31, 2016 Amgen, Inc. 10 % 16 % Ypsomed Distribution AG 31 % 19 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis	The following table provides a summary of assets that are measured at fair value as of December 31, 2017 and 2016 , aggregated by the level in the fair value hierarchy within which those measurements fall: Fair Value Measurements (in thousands) Total Level 1 Level 2 Level 3 December 31, 2017 Recurring fair value measurements: Cash equivalents: Money market mutual funds $ 236,936 $ 236,936 $ — $ — U.S. government and agency bonds 5,000 5,000 — — Corporate bonds — — — — Certificates of deposit — — — — Total cash equivalents $ 241,936 $ 241,936 $ — $ — Short-term investments: U.S. government bonds $ 112,076 $ 90,703 $ 21,373 $ — Corporate bonds 47,681 — 47,681 — Certificates of deposit 7,722 — 7,722 — Total short-term investments $ 167,479 $ 90,703 $ 76,776 $ — Long-term investments: U.S. government and agency bonds $ 92,464 $ 49,651 $ 42,813 $ — Corporate bonds 27,812 — 27,812 — Certificates of deposit 5,273 — 5,273 — Total long-term investments $ 125,549 $ 49,651 $ 75,898 $ — December 31, 2016 Recurring fair value measurements: Cash equivalents: Money market mutual funds $ 93,467 $ 93,467 $ — $ — Corporate bonds 4,203 — 4,203 — Certificates of deposit 735 — 735 — Total cash equivalents $ 98,405 $ 93,467 $ 4,938 $ — Short-term investments: U.S. government and agency bonds $ 79,093 $ 49,963 $ 29,130 $ — Corporate bonds 56,653 — 56,653 — Certificates of deposit 25,650 — 25,650 — Total short-term investments $ 161,396 $ 49,963 $ 111,433 $ —
Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis	The carrying amounts, net of unamortized discounts and issuance costs, and the estimated fair values of the Company's convertible debt as of December 31, 2017 and 2016 are as follows: December 31, 2017 December 31, 2016 (in thousands) Carrying Value Estimated Fair Value Carrying Estimated Fair 2% Convertible Senior Notes $ 3,421 $ 5,467 $ 59,737 $ 71,909 1.375% Convertible Senior Notes 276,172 407,652 — — 1.25% Convertible Senior Notes 286,580 450,881 273,031 320,969 Total $ 566,173 $ 864,000 $ 332,768 $ 392,878

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Investments	Amortized costs, gross unrealized holding gains and losses, and fair values at December 31, 2017 are as follows: (in thousands) Amortized cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2017 U.S. government and agency bonds $ 112,311 $ — $ (235 ) $ 112,076 Corporate bonds 47,713 3 (35 ) 47,681 Certificates of deposit 7,722 — — 7,722 Total short-term investments $ 167,746 $ 3 $ (270 ) $ 167,479 U.S. government and agency bonds $ 92,677 $ — $ (213 ) $ 92,464 Corporate bonds 27,871 — (59 ) 27,812 Certificates of deposit 5,273 — — 5,273 Total long-term investments $ 125,821 $ — $ (272 ) $ 125,549 December 31, 2016 U.S. government and agency bonds $ 79,211 $ — $ (118 ) $ 79,093 Corporate bonds 56,742 — (89 ) 56,653 Certificates of deposit 25,650 — — 25,650 Total short-term investments $ 161,603 $ — $ (207 ) $ 161,396 Total long-term investments $ — $ — $ — $ —

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Schedule of gross receivable from major customers	Revenue for customers comprising more than 10% of total revenue were as follows: Twelve Months Ended December 31, 2017 2016 2015 Amgen, Inc. 15% 17% 10% Ypsomed Distribution AG 22% 16% 12% RGH Enterprises, Inc. 11% 10% 13% Customers that represented greater than 10% of gross accounts receivable as of December 31, 2017 , and 2016 were as follows: As of December 31, 2017 December 31, 2016 Amgen, Inc. 10 % 16 % Ypsomed Distribution AG 31 % 19 %
Components of Accounts Receivable	The components of accounts receivable are as follows: (in thousands) As of December 31, 2017 December 31, 2016 Trade receivables $ 55,914 $ 31,714 Allowance for doubtful accounts (2,541 ) (2,911 ) Total accounts receivable $ 53,373 $ 28,803

Inventories, Net (Tables)

Inventories, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Components Of Inventories [Abstract]
Components of Inventories	The components of inventories are as follows: (in thousands) As of December 31, 2017 December 31, 2016 Raw materials $ 2,146 $ 1,911 Work-in-process 23,918 15,681 Finished goods, net 7,729 17,922 Total inventories $ 33,793 $ 35,514

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	Property and equipment related to continuing operations consist of the following: Estimated Useful Life (Years) As of (in thousands) December 31, 2017 December 31, 2016 Land n/a $ 2,525 $ — Machinery and equipment 2-7 60,878 53,246 Lab equipment 3-7 1,038 694 Computers 3-5 3,659 2,833 Office furniture and fixtures 3-5 2,521 1,960 Leasehold improvement * 1,425 1,126 Construction in process — 87,397 23,859 Total property and equipment $ 159,443 $ 83,718 Less: accumulated depreciation (51,579 ) (38,965 ) Total property and equipment, net $ 107,864 $ 44,753 ____________________________________ * Lesser of lease term or useful life of asset.

Other Intangible Assets, Net (T

Other Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Other Intangible Assets	Other intangible assets consist of the following: As of December 31, 2017 December 31, 2016 (in thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer and contractual relationships $ 2,135 $ (1,764 ) $ 371 $ 1,994 $ (1,466 ) $ 528 Internal use software 7,545 (3,565 ) 3,980 4,064 (2,551 ) 1,513 Total intangible assets $ 9,680 $ (5,329 ) $ 4,351 $ 6,058 $ (4,017 ) $ 2,041
Amortization Expense Expected for Next Five Years	Amortization expense expected for the next five years and thereafter is as follows: (in thousands) Years Ending December 31, Customer and Contractual Relationships Internal-Use Software Total 2018 $ 165 $ 1,235 $ 1,400 2019 138 984 1,122 2020 68 744 812 2021 — 623 623 2022 — 383 383 Thereafter — 11 11 Total $ 371 $ 3,980 $ 4,351

Accrued Expenses and Other Cu40

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities related to continuing operations consist of the following: Years Ended December 31, (in thousands) 2017 2016 Employee compensation and related costs $ 34,942 $ 21,999 Professional and consulting services 9,273 6,753 Supplier charges 3,542 2,886 Warranty 1,653 1,642 Accrued interest 2,030 1,303 Accrued freight 1,148 595 Other 6,668 6,050 Total accrued expenses and other current liabilities $ 59,256 $ 41,228
Reconciliation of Changes in Product Warranty Liability	A reconciliation of the changes in the Company’s product warranty liability is as follows: Years Ended December 31, (in thousands) 2017 2016 Product warranty liability at the beginning of the period $ 4,388 $ 4,152 Warranty expense 6,127 4,602 Warranty claims settled (5,178 ) (4,366 ) Product warranty liability at the end of the period $ 5,337 $ 4,388 As of (in thousands) December 31, 2017 December 31, 2016 Composition of balance: Short-term $ 1,653 $ 1,642 Long-term 3,684 2,746 Product warranty liability at the end of the period $ 5,337 $ 4,388

Convertible Debt (Tables)

Convertible Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Outstanding Convertible Debt and Related Deferred Financing Costs	The Company had outstanding convertible debt and related deferred financing costs on its consolidated balance sheet as follows: As of (in thousands) December 31, 2017 December 31, 2016 Principal amount of 2.0% Convertible Senior Notes $ 3,664 $ 67,084 Principal amount of 1.25% Convertible Senior Notes 345,000 345,000 Principal amount of 1.375% Convertible Senior Notes 402,500 — Unamortized debt discount (170,448 ) (69,684 ) Deferred financing costs (14,543 ) (9,632 ) Long-term debt, net of discount and issuance costs $ 566,173 $ 332,768
Interest and Other Expense	Interest expense related to the convertible notes is as follows: Years Ended December 31, (in thousands) 2017 2016 2015 Contractual coupon interest $ 6,282 $ 4,467 $ 4,025 Accretion of debt discount 15,931 8,800 6,552 Amortization of debt issuance costs 2,077 1,270 1,126 Total interest expense related to convertible notes $ 24,290 $ 14,537 $ 11,703 Interest expense related to convertible notes for the year ended December 31, 2017 is as follows: (in thousands) 1.375% 1.25% 2.0% Total Contractual coupon interest $ 769 $ 4,336 $ 1,177 $ 6,282 Amortization of debt discount and issuance costs 1,998 13,549 2,461 18,008 Total interest expense $ 2,767 $ 17,885 $ 3,638 $ 24,290

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Aggregate Future Minimum Lease Payments	The aggregate future minimum lease payments related to these leases as of December 31, 2017 are as follows: (in thousands) Years Ending December 31, Minimum Lease Payments 2018 3,025 2019 2,961 2020 2,611 2021 2,383 2022 2,131 Thereafter — Total $ 13,111

Stock-Based Compensation and 43

Stock-Based Compensation and Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Estimated grant date fair value of employee stock options - Black-Scholes option pricing model valuation assumptions	The estimated grant date fair values of the employee stock options were calculated using the Black-Scholes option pricing model, based on the following assumptions: Years Ended December 31, 2017 2016 2015 Risk-free interest rate 1.66% - 1.85% 0.99% - 1.91% 1.16% - 1.75% Expected term (in years) 4.7 - 5.3 5.1 - 5.4 4.9 - 5.3 Dividend yield — — — Expected volatility 38% - 39% 38% - 40% 37% - 38%
Stock Option Activity	The following summarizes the activity under the Company’s stock option plans: Number of Options (#) Weighted Average Exercise Price ($) Weighted Average Remaining Contractual Term Aggregate Intrinsic Value ($) (In thousands) Outstanding at December 31, 2016 3,441,303 $ 32.27 Granted 543,045 45.99 Exercised (505,207 ) 27.72 $ 11,846 Canceled (101,921 ) 34.29 Outstanding at December 31, 2017 3,377,220 $ 35.10 7.6 $ 114,505 Vested, December 31, 2017 1,934,398 $ 33.51 7.0 $ 68,654 Vested or expected to vest, December 31, 2017 (1) 3,211,982 $ 34.93 7.6 $ 109,462 (1) Represents total outstanding stock options as of December 31, 2017 , adjusted for the estimated forfeiture.
Summary of Restricted Stock Units	The following table summarizes the status of the Company’s restricted stock units: Number of Shares (#) Weighted Average Fair Value ($) Outstanding at December 31, 2016 962,219 $ 31.14 Granted 436,066 47.64 Vested (386,284 ) 31.79 Forfeited (17,637 ) 33.68 Outstanding at December 31, 2017 994,364 $ 38.08

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Tax Benefit (Expense)	Income tax expense from continuing operations consists of the following: Years Ended December 31, (in thousands) 2017 2016 2015 Current: Federal $ — $ — $ — State 151 52 72 Non-U.S. 603 539 321 Total current expense 754 591 393 Deferred: Federal (347 ) — — State 91 — — Non-U.S. (241 ) (199 ) (181 ) Total deferred expense (497 ) (199 ) (181 ) Total income tax expense $ 257 $ 392 $ 212
Reconciliation of Income Tax Expense (Benefit) at Statutory Federal Income Tax Rate	The following table reconciles the federal statutory income rate to the Company's effective income tax rate: Year Ended December 31, 2017 2016 2015 Tax at U.S. statutory rate 34.00 % 34.00 % 34.00 % Changes from statutory rate: State taxes, net of federal benefit 10.21 (10.86 ) 3.06 Tax credits 13.28 0.03 1.51 Permanent items (0.55 ) (11.03 ) (2.09 ) Change in enacted rates 0.98 — — Change in valuation allowance (57.91 ) (13.45 ) (37.11 ) Other (0.98 ) (0.15 ) 0.28 Effective income tax rate (0.97 )% (1.46 )% (0.35 )%
Components of Company's Deferred Tax Assets (Liabilities)	Significant components of the Company’s deferred tax assets (liabilities) consists of the following: Year Ended December 31, (in thousands) 2017 2016 Deferred tax assets: Net operating loss carryforwards $ 129,184 $ 169,203 Start up expenditures 462 929 Tax credits 12,705 8,007 Provision for bad debts 824 1,330 Depreciation and amortization 3,068 6,368 Capital loss carryforwards 12,850 18,961 Stock-based compensation 9,799 10,359 Other 4,449 4,701 Total deferred tax assets $ 173,341 $ 219,858 Deferred tax liabilities: Prepaid assets $ (1,326 ) $ (1,173 ) Amortization of acquired intangibles (5 ) (33 ) Amortization of debt discount (43,083 ) (25,977 ) Goodwill (633 ) (855 ) Other (259 ) (313 ) Total deferred tax liabilities $ (45,306 ) $ (28,351 ) Valuation allowance $ (127,927 ) $ (191,922 ) Net deferred tax liabilities $ 108 $ (415 )

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Potential Common Shares Excluded From Computation Of Diluted Net Loss Per Share [Abstract]
Potential Common Shares Excluded from Computation of Diluted Net Loss per Share	Potential dilutive common share equivalents consist of the following: Years Ended December 31, 2017 2016 2015 1.375% Convertible Senior Notes 4,319,429 — — 2.00% Convertible Senior Notes 78,783 1,442,433 4,327,257 1.25% Convertible Senior Notes 5,910,954 5,910,954 — Unvested restricted stock units 994,364 962,219 811,965 Outstanding stock options 3,377,220 3,441,303 2,999,199 Total dilutive common shares 14,680,750 11,756,909 8,138,421

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Revenue by company products	Worldwide revenue for the Company's products is categorized as follows: Years Ended December 31, (in thousands) 2017 2016 2015 U.S. Omnipod $ 271,597 $ 229,785 $ 189,604 International Omnipod 119,953 71,889 40,339 Drug Delivery 72,218 65,315 33,950 Total $ 463,768 $ 366,989 $ 263,893
Revenue by geographic region of customer's shipping location	Geographic information about revenue, based on the region of the customer's shipping location, is as follows: Years Ended December 31, (in thousands) 2017 2016 2015 United States $ 343,815 $ 295,100 $ 223,554 All other 119,953 71,889 40,339 Total $ 463,768 $ 366,989 $ 263,893
Long-lived assets, net, excluding goodwill and other intangible assets by geographic area	Geographic information about long-lived assets, net, excluding goodwill and other intangible assets is as follows: (in thousands) December 31, 2017 December 31, 2016 United States $ 89,404 $ 19,341 China 18,217 25,431 Other 434 197 Total $ 108,055 $ 44,969

Business Combination (Tables)

Business Combination (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	The aggregate purchase price of approximately $4.7 million consisted of cash paid at closing and was allocated to the fair value of assets acquired and liabilities assumed as follows: (in thousands) Goodwill $ 2,403 Contractual relationships 2,100 Inventory step-up 230 Assumed liabilities (18 ) $ 4,715

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Summary of Operating Results and Balance Sheet Location of Discontinued Operations	The following is a summary of the operating results of Neighborhood Diabetes included in discontinued operations for the year ended December 31, 2016 and 2015 : Years Ended December 31, (In thousands) 2016 2015 Discontinued operations: Revenue (1) $ 7,730 $ 60,332 Cost of revenue 5,468 45,449 Gross profit 2,262 14,883 Operating expenses: Sales and marketing 1,542 9,945 General and administrative (2) (3) 1,853 16,967 Total operating expenses 3,395 26,912 Operating loss (1,133 ) (12,029 ) Interest and other income (expense), net (128 ) 190 Loss from discontinued operations before taxes (1,261 ) (11,839 ) Income tax expense 408 79 Net loss from discontinued operations $ (1,669 ) $ (11,918 ) (1) Revenue for the year ended December 31, 2016 includes revenue from operations of Neighborhood Diabetes through the date of sale in February 2016. (2) Included in general and administration expenses for the year ended December 31, 2015 was a charge of $9.1 million related to the impairment of Neighborhood Diabetes asset group. (3) Included in general and administration expenses for the year ended December 31, 2015 was $0.5 million of stock-based compensation expense from discontinued operations related to share-based awards. Stock-based compensation expense from discontinued operations related to share-based awards was not significant for the year ended December 31, 2016.

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Data (Unaudited) [Abstract]
Selected Quarterly Data	2017 Quarters Ended December 31 September 30 June 30 March 31 (In thousands, except per share data) Revenue $ 130,524 $ 121,775 $ 109,756 $ 101,713 Gross profit 79,508 73,624 64,639 59,398 Operating (loss) income (768 ) 2,047 (3,358 ) (5,308 ) Net loss $ (6,860 ) $ (2,227 ) $ (7,767 ) $ (9,977 ) Net loss per share $ (0.12 ) $ (0.04 ) $ (0.13 ) $ (0.17 ) 2016 Quarters Ended December 31 (1) September 30 June 30 March 31 (In thousands, except per share data) Revenue $ 103,575 $ 94,871 $ 87,330 $ 81,213 Gross profit 60,937 55,641 50,457 44,051 Operating (loss) income (4,135 ) 2,418 (1,288 ) (7,699 ) Net loss from continuing operations, net of taxes (9,153 ) (3,017 ) (4,351 ) (10,689 ) Income (loss) from discontinued operations, net of taxes 34 (64 ) 153 (1,792 ) Net loss $ (9,119 ) $ (3,081 ) $ (4,198 ) $ (12,481 ) Net loss per share from continuing operations $ (0.16 ) $ (0.05 ) $ (0.08 ) $ (0.19 ) Net loss per share from discontinued operations $ — $ — $ — $ (0.03 ) (1) Included in net loss from continuing operations for the fourth quarter of 2016 was a charge of $6.1 million related to in-process internally developed software.

Nature of Business (Details)

Nature of Business (Details)	Dec. 31, 2017in
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of inches of tubing in conventional insulin pump	42

Summary of Significant Accoun51

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2017USD ($)segmentlocation	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Significant Accounting Policies [Line Items]
Restricted Cash	$ 500,000	$ 1,200,000
Number of operating segments | segment	1
Goodwill impairment loss	$ 0	0	$ 0
Return period	45 days
Return period Canada	90 days
Deferred revenue	$ 3,200,000	1,900,000
Shipping and handling costs	$ 5,000,000	4,100,000	$ 3,700,000
Number of accredited financial institutions which the Company maintains the majority of its cash | location	1
Total property and equipment	$ 159,443,000	83,718,000
Accumulated depreciation	51,579,000	38,965,000
Increase to deferred tax assets	108,000
Prepaid expenses and other current assets	9,949,000	7,073,000
Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Increase to deferred tax assets	23,800,000
Other Noncurrent Liabilities
Significant Accounting Policies [Line Items]
Deferred revenue	$ 900,000	600,000
Internal-Use Software | Accounting Standards Update 2016-19
Significant Accounting Policies [Line Items]
Total property and equipment		(4,100,000)
Accumulated depreciation		$ 2,600,000
Flex Ltd. | Supplier Concentration Risk | Accounts Payable
Significant Accounting Policies [Line Items]
Concentration risk, percentage	20.00%	16.00%
Pro Forma | Minimum | Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Significant Accounting Policies [Line Items]
Expected contract asset	$ 4,000,000
Expected contract liability	1,000,000
Prepaid expenses and other current assets	18,000,000
Pro Forma | Maximum | Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Significant Accounting Policies [Line Items]
Expected contract asset	6,000,000
Expected contract liability	3,000,000
Prepaid expenses and other current assets	$ 20,000,000

Summary of Significant Accoun52

Summary of Significant Accounting Policies - Goodwill Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning balance	$ 39,677	$ 39,607
Foreign currency adjustment	163	70
Ending balance	$ 39,840	$ 39,677

Summary of Significant Accoun53

Summary of Significant Accounting Policies - Schedule of Customer Concentration (Details) - Customer Concentration Risk - Sales Revenue, Net	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amgen, Inc.
Revenue, Major Customer [Line Items]
Concentration risk, percentage	15.00%	17.00%	10.00%
Ypsomed Distribution AG
Revenue, Major Customer [Line Items]
Concentration risk, percentage	22.00%	16.00%	12.00%
RGH Enterprises, Inc.
Revenue, Major Customer [Line Items]
Concentration risk, percentage	11.00%	10.00%	13.00%

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets Measured on a Recurring and Nonrecurring Basis (Details) - Recurring fair value measurements: - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	$ 241,936	$ 98,405
Short-term investments:	167,479	161,396
Long-term investments:	125,549
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	241,936	93,467
Short-term investments:	90,703	49,963
Long-term investments:	49,651
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	4,938
Short-term investments:	76,776	111,433
Long-term investments:	75,898
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Short-term investments:	0	0
Long-term investments:	0
Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	236,936	93,467
Money market mutual funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	236,936	93,467
Money market mutual funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Money market mutual funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
U.S. government and agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	5,000
Short-term investments:	112,076	79,093
Long-term investments:	92,464
U.S. government and agency bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	5,000
Short-term investments:	90,703	49,963
Long-term investments:	49,651
U.S. government and agency bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0
Short-term investments:	21,373	29,130
Long-term investments:	42,813
U.S. government and agency bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0
Short-term investments:	0	0
Long-term investments:	0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	4,203
Short-term investments:	47,681	56,653
Long-term investments:	27,812
Corporate bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Short-term investments:	0	0
Long-term investments:	0
Corporate bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	4,203
Short-term investments:	47,681	56,653
Long-term investments:	27,812
Corporate bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Short-term investments:	0	0
Long-term investments:	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	735
Short-term investments:	7,722	25,650
Long-term investments:	5,273
Certificates of deposit | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Short-term investments:	0	0
Long-term investments:	0
Certificates of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	735
Short-term investments:	7,722	25,650
Long-term investments:	5,273
Certificates of deposit | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents:	0	0
Short-term investments:	0	$ 0
Long-term investments:	$ 0

Fair Value Measurements - Sch55

Fair Value Measurements - Schedule of Liabilities Measure on Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2014
2% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	2.00%	2.00%		2.00%
1.375% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	1.375%
1.25% Convertible Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, interest rate	1.25%	1.25%	1.25%
Carrying Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 566,173	$ 332,768
Carrying Value | 2% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	3,421	59,737
Carrying Value | 1.375% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	276,172	0
Carrying Value | 1.25% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	286,580	273,031
Estimated Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	864,000	392,878
Estimated Fair Value | 2% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	5,467	71,909
Estimated Fair Value | 1.375% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	407,652	0
Estimated Fair Value | 1.25% Convertible Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible senior notes	$ 450,881	$ 320,969

Investments - Schedule of Inves

Investments - Schedule of Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Minimum
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, maturity date range	15 days
Maximum
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, maturity date range	23 months
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 167,746	$ 161,603
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(270)	(207)
Fair Value	167,479	161,396
Short-term Investments | U.S. government and agency bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	112,311	79,211
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(235)	(118)
Fair Value	112,076	79,093
Short-term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	47,713	56,742
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(35)	(89)
Fair Value	47,681	56,653
Short-term Investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	7,722	25,650
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	7,722	25,650
Long Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	125,821	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(272)	0
Fair Value	125,549	$ 0
Long Term Investments | U.S. government and agency bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	92,677
Gross Unrealized Gains	0
Gross Unrealized Losses	(213)
Fair Value	92,464
Long Term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	27,871
Gross Unrealized Gains	0
Gross Unrealized Losses	(59)
Fair Value	27,812
Long Term Investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,273
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	$ 5,273

Accounts Receivable, Net - Comp

Accounts Receivable, Net - Components of Accounts Receivable (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Components of Accounts Receivable from Continuing Operations [Line Items]
Trade receivables	$ 55,914	$ 31,714
Allowance for doubtful accounts	(2,541)	(2,911)
Total accounts receivable	$ 53,373	$ 28,803
Amgen, Inc. | Customer Concentration Risk | Accounts Receivable
Components of Accounts Receivable from Continuing Operations [Line Items]
Concentration risk, percentage	10.00%	16.00%
Ypsomed Distribution AG | Customer Concentration Risk | Accounts Receivable
Components of Accounts Receivable from Continuing Operations [Line Items]
Concentration risk, percentage	31.00%	19.00%

Inventories - Components of Inv

Inventories - Components of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Disclosure Components Of Inventories [Abstract]
Raw materials	$ 2,146	$ 1,911
Work-in-process	23,918	15,681
Finished goods, net	7,729	17,922
Total inventories	$ 33,793	$ 35,514

Property and Equipment, Net - C

Property and Equipment, Net - Component of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 159,443	$ 83,718
Less: accumulated depreciation	(51,579)	(38,965)
Total property and equipment, net	107,864	44,753
Land
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,525	0
Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Total property and equipment	$ 60,878	53,246
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,038	694
Computers
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Total property and equipment	$ 3,659	2,833
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	2,521	1,960
Leasehold improvement
Property, Plant and Equipment [Line Items]
Total property and equipment	1,425	1,126
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 87,397	$ 23,859
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	2 years
Minimum | Lab equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Minimum | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Maximum | Lab equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	7 years
Maximum | Computers
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Maximum | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation	$ 12.7	$ 12.6	$ 11
Interest costs capitalized	$ 3.1	$ 0.5	$ 0.2

Other Intangible Assets, Net -

Other Intangible Assets, Net - Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 9,680	$ 6,058
Accumulated Amortization	(5,329)	(4,017)
Net Book Value	4,351	2,041
Customer and Contractual Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,135	1,994
Accumulated Amortization	(1,764)	(1,466)
Net Book Value	371	528
Internal-Use Software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,545	4,064
Accumulated Amortization	(3,565)	(2,551)
Net Book Value	$ 3,980	$ 1,513

Other Intangible Assets, Net 62

Other Intangible Assets, Net - Amortization Expense Expected for Next Five Years (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Expected Amortization Expense [Line Items]
2,018	$ 1,400
2,019	1,122
2,020	812
2,021	623
2,022	383
Thereafter	11
Total	4,351	$ 2,041
Customer and Contractual Relationships
Expected Amortization Expense [Line Items]
2,018	165
2,019	138
2,020	68
2,021	0
2,022	0
Thereafter	0
Total	371
Internal-Use Software
Expected Amortization Expense [Line Items]
2,018	1,235
2,019	984
2,020	744
2,021	623
2,022	383
Thereafter	11
Total	$ 3,980

Other Intangible Assets, Net 63

Other Intangible Assets, Net - Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Impairments and other	$ 89	$ 6,234	$ 9,086
Gross Carrying Amount	9,680	6,058
Accumulated Amortization	(5,329)	(4,017)
Amortization of other intangible assets	1,200	1,200
Customer and Contractual Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,135	1,994
Accumulated Amortization	$ (1,764)	(1,466)
Intangible asset, weighted average amortization period	3 years
Internal-Use Software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 7,545	4,064
Accumulated Amortization	$ (3,565)	$ (2,551)
Intangible asset, weighted average amortization period	4 years
GSK Asset Acquisition | Customer and Contractual Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Other intangible assets cost			$ 2,100
Estimated useful life			5 years
General and Administrative Expense
Acquired Finite-Lived Intangible Assets [Line Items]
Impairments and other	$ 6,100

Accrued Expenses and Other Cu64

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Employee compensation and related costs	$ 34,942	$ 21,999
Professional and consulting services	9,273	6,753
Supplier charges	3,542	2,886
Warranty	1,653	1,642
Accrued interest	2,030	1,303
Accrued freight	1,148	595
Other	6,668	6,050
Total accrued expenses and other current liabilities	$ 59,256	$ 41,228

Accrued Expenses and Other Cu65

Accrued Expenses and Other Current Liabilities - Reconciliation of Changes in Product Warranty Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Product warranty liability at the beginning of the period	$ 4,388	$ 4,152
Warranty expense	6,127	4,602
Warranty claims settled	(5,178)	(4,366)
Product warranty liability at the end of the period	$ 5,337	$ 4,388

Accrued Expenses and Other Cu66

Accrued Expenses and Other Current Liabilities - Product Warranty Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Composition of balance:
Short-term	$ 1,653	$ 1,642
Long-term	3,684	2,746
Total warranty balance	$ 5,337	$ 4,388	$ 4,152

Accrued Expenses and Other Cu67

Accrued Expenses and Other Current Liabilities - Narrative (Detail)	12 Months Ended
	Dec. 31, 2017
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

Capital Lease Obligations - Add

Capital Lease Obligations - Additional information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Capital Leased Assets [Line Items]
Capital leased assets	$ 0
Final minimum lease payment	269,000	$ 5,518,000	$ 5,576,000
Future minimum lease payments	$ 0
Interest expense		400,000	1,200,000
Machinery and equipment
Capital Leased Assets [Line Items]
Capital leased assets		13,700,000
Estimated Useful Life (Years)	5 years
Amortization expense	$ 2,700,000	$ 2,700,000	$ 2,500,000

Convertible Debt - Outstanding

Convertible Debt - Outstanding Convertible Debt and Related Deferred Financing Costs (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2014
Debt Instrument [Line Items]
Unamortized debt discount	$ (170,448)	$ (69,684)
Deferred financing costs	(14,543)	(9,632)
Long-term debt, net of discount and issuance costs	$ 566,173	$ 332,768
2% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	2.00%	2.00%		2.00%
Convertible debt principal amount, gross	$ 3,664	$ 67,084
Long-term debt, net of discount and issuance costs	$ 3,400
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	1.25%	1.25%	1.25%
Convertible debt principal amount, gross	$ 345,000	$ 345,000
Long-term debt, net of discount and issuance costs	$ 286,600
1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	1.375%
Convertible debt principal amount, gross	$ 402,500	$ 0

Convertible Debt - Interest Exp

Convertible Debt - Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Contractual coupon interest	$ 6,282	$ 4,467	$ 4,025
Accretion of debt discount	15,931	8,800	6,552
Amortization of debt issuance costs	2,077	1,270	1,126
Total interest expense related to convertible notes	24,290	14,537	11,703
Amortization of debt discount and issuance costs	18,008	$ 10,068	$ 7,678
Total interest expense	24,290
2% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	1,177
Amortization of debt discount and issuance costs	2,461
Total interest expense	3,638
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	4,336
Amortization of debt discount and issuance costs	13,549
Total interest expense	17,885
1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Contractual coupon interest	769
Amortization of debt discount and issuance costs	1,998
Total interest expense	$ 2,767

Convertible Debt - Narrative (D

Convertible Debt - Narrative (Detail)	1 Months Ended			3 Months Ended	12 Months Ended
	Nov. 30, 2017USD ($)$ / shares	Sep. 30, 2016USD ($)$ / shares	Jun. 30, 2014USD ($)$ / shares	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Long-term debt, net				$ 566,173,000	$ 566,173,000	$ 332,768,000
Contractual coupon interest					6,282,000	4,467,000	$ 4,025,000
Unamortized discount				170,448,000	170,448,000	69,684,000
Loss on extinguishment of long-term debt					609,000	2,551,000	0
Amortization of debt discount and issuance costs					18,008,000	10,068,000	$ 7,678,000
Long-term debt, net of discount and issuance costs				566,173,000	566,173,000	332,768,000
1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Convertible debt principal amount, gross				$ 402,500,000	$ 402,500,000	0
Debt, interest rate				1.375%	1.375%
Long-term debt, net				$ 276,200,000	$ 276,200,000
Contractual coupon interest					769,000
Debt instrument, face amount	$ 402,500,000
Amortization of debt discount and issuance costs					1,998,000
1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Convertible debt principal amount, gross				$ 345,000,000	$ 345,000,000	$ 345,000,000
Debt, interest rate		1.25%		1.25%	1.25%	1.25%
Contractual coupon interest					$ 4,336,000
Debt conversion rate		17.1332
Principal amount per note used in conversion rate		$ 1,000
Conversion price, per share (USD per share) | $ / shares		$ 58.37
Nonconvertible debt borrowing rate		5.80%
Debt discount amortization period		5 years
Debt issuance costs incurred		$ 11,300,000
Finance costs reclassified against equity		2,200,000
Debt instrument, face amount		345,000,000
Amortization of debt discount and issuance costs					13,549,000
Long-term debt, net of discount and issuance costs				$ 286,600,000	286,600,000
1.25% Convertible Senior Notes | Investor
Debt Instrument [Line Items]
Unamortized discount		66,700,000
2% Convertible Senior Notes
Debt Instrument [Line Items]
Convertible debt principal amount, gross				$ 3,664,000	$ 3,664,000	$ 67,084,000
Debt, interest rate			2.00%	2.00%	2.00%	2.00%
Contractual coupon interest					$ 1,177,000
Debt conversion rate			21.5019
Principal amount per note used in conversion rate			$ 1,000
Conversion price, per share (USD per share) | $ / shares			$ 46.51
Nonconvertible debt borrowing rate			6.20%
Debt discount amortization period			5 years
Debt issuance costs incurred			$ 6,700,000
Finance costs reclassified against equity			1,200,000
Debt instrument, face amount			201,300,000
Amount allocated to debt		121,400,000				$ 121,400,000
Amount allocated to equity		32,900,000
Loss on extinguishment of long-term debt		2,600,000
Amortization of debt discount and issuance costs					2,461,000
Long-term debt, net of discount and issuance costs				$ 3,400,000	3,400,000
Debt instrument, repurchased face amount		134,200,000
Payments of long-term debt		$ 153,600,000
2% Convertible Senior Notes | Investor
Debt Instrument [Line Items]
Unamortized discount			$ 35,600,000
3.75% Convertible Notes
Debt Instrument [Line Items]
Interest expense related to Notes						0
Amortization of debt discount and issuance costs						$ 0
First 180 Days | 2% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, additional interest in event of reporting violation			0.25%
Debt instrument, redemption period			180 days
Up to 360 Days | 1.25% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, redemption period		360 days
Up to 360 Days | 1.25% Convertible Senior Notes | New Debt
Debt Instrument [Line Items]
Nonconvertible debt borrowing rate		0.50%
Up to 360 Days | 2% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, additional interest in event of reporting violation			0.50%
Debt instrument, redemption period			360 days
Senior Notes | 1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt, interest rate	1.375%
Debt conversion rate	10.7315
Principal amount per note used in conversion rate	$ 1,000
Conversion price, per share (USD per share) | $ / shares	$ 93.18
Nonconvertible debt borrowing rate	6.80%
Debt discount amortization period	7 years
Debt issuance costs incurred				10,900,000	10,900,000
Finance costs reclassified against equity				3,300,000
Debt issuance costs as a reduction of debt				$ 7,600,000	7,600,000
Net proceeds from senior notes	$ 98,600,000
Amount allocated to debt	59,400,000
Amount allocated to equity	39,200,000
Loss on extinguishment of long-term debt					$ 600,000
Senior Notes | Investor | 1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Unamortized discount	120,700,000
Debt instrument, face amount	$ 63,400,000
Senior Notes | Up to 365 Days | 1.375% Convertible Senior Notes
Debt Instrument [Line Items]
Debt instrument, additional interest in event of reporting violation	0.50%
Debt instrument, redemption period	360 days

Commitments and Contingencies -

Commitments and Contingencies - Operating Leases (Detail) ft² in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)ft²	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Operating Leased Assets [Line Items]
Rent expense | $	$ 2.8	$ 2.5	$ 1.9
Other Facilities
Operating Leased Assets [Line Items]
Operating lease area (sqft)	14
Billerica Massachusetts | Laboratory And Office Space
Operating Leased Assets [Line Items]
Operating lease area (sqft)	100
Billerica Massachusetts | Warehouse
Operating Leased Assets [Line Items]
Operating lease area (sqft)	29

Commitments and Contingencies73

Commitments and Contingencies - Aggregate Future Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 3,025
2,019	2,961
2,020	2,611
2,021	2,383
2,022	2,131
Thereafter	0
Total	$ 13,111

Stock-Based Compensation and 74

Stock-Based Compensation and Stockholders' Equity - Stock-Based Compensation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$ 31.9	$ 23.8	$ 18.7
Total unrecognized compensation expense	$ 41.2

Stock-Based Compensation and 75

Stock-Based Compensation and Stockholders' Equity - Equity Award Plans (Details) shares in Millions	12 Months Ended
	Dec. 31, 2017shares
Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years 4 months 18 days
2007 Plan | Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in sharers)	5.1
2017 Plan | Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years

Stock-Based Compensation and 76

Stock-Based Compensation and Stockholders' Equity - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in sharers)	543,045
Weighted average grant date fair value (USD per share)	$ 17.28	$ 11.60	$ 11.09
Intrinsic value, exercised in the period	$ 11,846	$ 4,600	$ 8,600
Closing stock price (USD per share)	$ 69
Stock-based compensation expense	$ 31,900	$ 23,800	$ 18,700
Total unrecognized compensation expense	$ 41,200
Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in sharers)	34,500	65,000	194,500
Vesting period	2 years 4 months 18 days
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 11,600	$ 9,900	$ 9,100
Total unrecognized compensation expense	$ 15,500
2017 Plan | Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
2007 Plan | Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years

Stock-Based Compensation and 77

Stock-Based Compensation and Stockholders' Equity - Employee Stock Options Calculated using Black-Scholes Option Pricing Model (Detail) - Employee Stock Option	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.66%	0.99%	1.16%
Risk-free interest rate, maximum	1.85%	1.91%	1.75%
Dividend yield	0.00%	0.00%	0.00%
Expected volatility, minimum	38.00%	38.00%	37.00%
Expected volatility, maximum	39.00%	40.00%	38.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	4 years 8 months 12 days	5 years 1 month 6 days	4 years 10 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 18 days	5 years 4 months 24 days	5 years 3 months 18 days

Stock-Based Compensation and 78

Stock-Based Compensation and Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Options
Beginning balance (in shares)	3,441,303
Granted (in shares)	543,045
Exercised (in shares)	(505,207)
Canceled (in shares)	(101,921)
Ending balance (in shares)	3,377,220	3,441,303
Vested, at end of period (in shares)	1,934,398
Vested or expected to vest (in shares)	3,211,982.23
Weighted Average Exercise Price
Beginning balance (in USD per share)	$ 32.27
Granted (in USD per share)	45.99
Exercised (in USD per share)	27.72
Canceled (in USD per share)	34.29
Ending balance (in USD per share)	35.10	$ 32.27
Vested, at end of period (in USD per share)	33.51
Vested or expected to vest (in USD per share)	$ 34.93
Options outstanding, weighted average remaining contractual life	7 years 7 months
Options exercisable, weighted average remaining contractual life	6 years 11 months 20 days
Expected to vest, outstanding, weighted average remaining contractual term	7 years 6 months 23 days
Intrinsic value, exercised in the period	$ 11,846	$ 4,600	$ 8,600
Intrinsic value, options outstanding	114,505
Intrinsic value, options vested	68,654
Intrinsic value, options vested and expected to vest	$ 109,462

Stock-Based Compensation and 79

Stock-Based Compensation and Stockholders' Equity - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 31.9	$ 23.8	$ 18.7
Total unrecognized compensation expense	$ 41.2
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in shares)	436,066	592,783
Stock-based compensation expense	$ 13.3	$ 10.2	8.1
Other than options - granted in period, weighted average fair value (USD per share)	$ 47.64
Other than options - grant date fair value	$ 20.8
Total unrecognized compensation expense	$ 25.7
Total unrecognized compensation expense weighted-average period	1 year 9 months 21 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in shares)	169,394,000	154,991
Stock-based compensation expense	$ 0.5	$ 1
Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Shares - Performance Expected To Be Achieved
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5.9	2.4
Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 0.6	$ 0.2	$ 0.1

Stock-Based Compensation and 80

Stock-Based Compensation and Stockholders' Equity - Summary of Restricted Stock Units (Detail) - Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Number of Shares
Beginning balance (in shares)	962,219
Granted (in shares)	436,066	592,783
Vested (in shares)	(386,284)
Forfeited (in shares)	(17,637)
Ending balance (in shares)	994,364	962,219
Weighted Average Fair Value
Beginning balance (in USD per share)	$ 31.14
Granted (in USD per share)	47.64
Vested (in USD per share)	31.79
Forfeited (in USD per share)	33.68
Ending balance (in USD per share)	$ 38.08	$ 31.14

Stock-Based Compensation and 81

Stock-Based Compensation and Stockholders' Equity - Employee Stock Purchase Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 31,900,000	$ 23,800,000	$ 18,700,000
Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	380,000
Annual maximum shares per employee (in shares)	800
Annual maximum common stock value purchase per employee	$ 25,000
Percentage of employees' compensation deduction for share purchase	10.00%
Purchase price percentage of fair market value	85.00%
Shares issued under employee stock purchase plan (in shares)	59,134	30,949	22,039
Stock-based compensation expense	$ 600,000	$ 200,000	$ 100,000

Stock-Based Compensation and 82

Stock-Based Compensation and Stockholders' Equity - Shareholder Rights Plan (Details)	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Percentage of outstanding shares, acquiring person requirement (percentage)	15.00%

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan [Abstract]
Percentage of eligible compensation employee may elect to contribute to the plan	100.00%
Company discretionary match percentage	50.00%
Employer matching percentage of employees contribution percentage	6.00%
Company match vesting period	1 year
Contributions by employer	$ 3	$ 1.6	$ 1.6

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Unrecognized tax benefits	$ 0
Tax benefit	300,000
Valuation allowance	60,500,000
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Increase (Decrease) In Deferred Tax Asset, Valuation Allowance	60,800,000
Tax expense related to repatriation tax	0
Reduction in net operating loss	800,000
Reduction in valuation allowance	800,000
Income tax expense		$ 408,000	$ 79,000
Foreign income tax expense	1,100,000	800,000	300,000
Undistributed earnings of foreign subsidiaries	6,400,000
Valuation allowance	127,927,000	191,922,000
Federal net operating loss carryforwards	543,600,000	535,700,000
State net operating loss carryforwards	250,600,000	216,200,000
Tax credits	12,705,000	8,007,000
Deferred tax assets that would impact equity	23,800,000
Increase to deferred tax assets	$ 108,000
Minimum
Significant Accounting Policies [Line Items]
Number of open tax years	2 years
Maximum
Significant Accounting Policies [Line Items]
Number of open tax years	4 years
Neighborhood Diabetes
Significant Accounting Policies [Line Items]
Income tax expense		$ 408,000	$ 79,000
Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Increase to deferred tax assets	$ 23,800,000
Net Deferred Tax Asset And Liability Changes
Significant Accounting Policies [Line Items]
Increase (decrease) in valuation allowance	(15,600,000)
Net Deferred Tax Liability
Significant Accounting Policies [Line Items]
Increase (decrease) in valuation allowance	$ 42,600,000
1.375% Convertible Senior Notes
Significant Accounting Policies [Line Items]
Debt, interest rate	1.375%

Income Taxes - Income Tax Benef

Income Taxes - Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 0	$ 0	$ 0
State	151	52	72
Non-U.S.	603	539	321
Total current expense	754	591	393
Deferred:
Federal	(347)	0	0
State	91	0	0
Non-U.S.	(241)	(199)	(181)
Total deferred expense	(497)	(199)	(181)
Total income tax expense	$ 257	$ 392	$ 212

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense (Benefit) at Statutory Federal Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Tax at U.S. statutory rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	10.21%	(10.86%)	3.06%
Tax credits	13.28%	0.03%	1.51%
Permanent items	(0.55%)	(11.03%)	(2.09%)
Change in enacted rates	0.98%	0.00%	0.00%
Change in valuation allowance	(57.91%)	(13.45%)	(37.11%)
Other	(0.98%)	(0.15%)	0.28%
Effective income tax rate	(0.97%)	(1.46%)	(0.35%)

Income Taxes - Components of Co

Income Taxes - Components of Company's Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 129,184	$ 169,203
Start up expenditures	462	929
Tax credits	12,705	8,007
Provision for bad debts	824	1,330
Depreciation and amortization	3,068	6,368
Capital loss carryforwards	12,850	18,961
Stock-based compensation	9,799	10,359
Other	4,449	4,701
Total deferred tax assets	173,341	219,858
Deferred tax liabilities:
Prepaid assets	(1,326)	(1,173)
Amortization of acquired intangibles	(5)	(33)
Amortization of debt discount	(43,083)	(25,977)
Goodwill	(633)	(855)
Other	(259)	(313)
Total deferred tax liabilities	(45,306)	(28,351)
Valuation allowance	(127,927)	(191,922)
Net deferred tax assets	$ 108
Net deferred tax liabilities		$ 415

Net Loss Per Share - Potential

Net Loss Per Share - Potential Common Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016	Jun. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	14,680,750	11,756,909	8,138,421
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	994,364	962,219	811,965
Outstanding options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3,377,220	3,441,303	2,999,199
1.375% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, interest rate	1.375%
1.375% Convertible Senior Notes | Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,319,429	0	0
2% Convertible Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, interest rate	2.00%	2.00%			2.00%
2% Convertible Senior Notes | Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	78,783	1,442,433	4,327,257
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% Convertible Senior Notes | Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	5,910,954	5,910,954	0

Segment Reporting (Details)

Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Reporting - Revenue by

Segment Reporting - Revenue by Product (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 463,768	$ 366,989	$ 263,893
U.S. Omnipod
Segment Reporting Information [Line Items]
Revenues	271,597	229,785	189,604
International Omnipod
Segment Reporting Information [Line Items]
Revenues	119,953	71,889	40,339
Drug Delivery
Segment Reporting Information [Line Items]
Revenues	$ 72,218	$ 65,315	$ 33,950

Segment Reporting - Revenue b91

Segment Reporting - Revenue by Geographic Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 463,768	$ 366,989	$ 263,893
United States
Segment Reporting Information [Line Items]
Revenues	343,815	295,100	223,554
All other
Segment Reporting Information [Line Items]
Revenues	$ 119,953	$ 71,889	$ 40,339

Segment Reporting - Long-lived

Segment Reporting - Long-lived Assets by Geographical Location (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Long-Lived Assets	$ 108,055	$ 44,969
United States
Segment Reporting Information [Line Items]
Long-Lived Assets	89,404	19,341
China
Segment Reporting Information [Line Items]
Long-Lived Assets	18,217	25,431
Other
Segment Reporting Information [Line Items]
Long-Lived Assets	$ 434	$ 197

Business Combination - Narrativ

Business Combination - Narrative (Details) $ in Millions	Jul. 07, 2015USD ($)
Business Combinations [Abstract]
Consideration transferred	$ 4.7

Business Combination - Schedule

Business Combination - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jul. 07, 2015
Business Combinations [Abstract]
Goodwill	$ 39,840	$ 39,677	$ 39,607	$ 2,403
Contractual relationships				2,100
Inventory step-up				230
Assumed liabilities				(18)
Assets acquired, liabilities assumed, net				$ 4,715

Discontinued Operations - Narra

Discontinued Operations - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended								12 Months Ended
	Jun. 30, 2016	Feb. 28, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operation, intra-entity amounts, discontinued operation after disposal, expense												$ 900,000
Revenue			$ 130,524,000	$ 121,775,000	$ 109,756,000	$ 101,713,000	$ 103,575,000	$ 94,871,000	$ 87,330,000	$ 81,213,000	$ 463,768,000	366,989,000	$ 263,893,000
Depreciation and amortization, discontinued operations											0	100,000	3,300,000
Discontinued operation, assets			0				0				0	0
Discontinued operation, liabilities			$ 0				$ 0				0	0
Cash provided by (used in) operating activities, discontinued operations											$ 0	2,000,000	3,200,000
Neighborhood Diabetes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue												300,000	$ 2,800,000
Neighborhood Diabetes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of interest in subsidiaries and affiliates	$ 1,200,000	$ 6,200,000
Neighborhood Diabetes | Neighborhood Diabetes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operation, intra-entity amounts, discontinued operation after disposal, revenue												$ 400,000

Discontinued Operations - Sched

Discontinued Operations - Schedule of Operating Results of Discontinued Business (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating expenses:
Income tax expense						$ 408	$ 79
Net loss from discontinued operations	$ 34	$ (64)	$ 153	$ (1,792)	$ 0	(1,669)	(11,918)
Neighborhood Diabetes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue						7,730	60,332
Cost of revenue						5,468	45,449
Gross profit						2,262	14,883
Operating expenses:
Sales and marketing						1,542	9,945
General and administrative						1,853	16,967
Total operating expenses						3,395	26,912
Operating loss						(1,133)	(12,029)
Interest and other income (expense), net						(128)	190
Loss from discontinued operations before taxes						(1,261)	(11,839)
Income tax expense						408	79
Net loss from discontinued operations						$ (1,669)	(11,918)
Impairment and other charges	$ 6,100						9,100
Stock-based compensation expense							$ 500

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	$ 130,524	$ 121,775	$ 109,756	$ 101,713	$ 103,575	$ 94,871	$ 87,330	$ 81,213	$ 463,768	$ 366,989	$ 263,893
Gross profit	79,508	73,624	64,639	59,398	60,937	55,641	50,457	44,051	277,169	211,086	133,271
Operating (loss) income	(768)	2,047	(3,358)	(5,308)	(4,135)	2,418	(1,288)	(7,699)	(7,387)	(10,704)	(48,736)
Net loss from continuing operations, net of taxes					(9,153)	(3,017)	(4,351)	(10,689)	(26,831)	(27,210)	(61,602)
Income (loss) from discontinued operations, net of taxes					34	(64)	153	(1,792)	0	(1,669)	(11,918)
Net loss	$ (6,860)	$ (2,227)	$ (7,767)	$ (9,977)	$ (9,119)	$ (3,081)	$ (4,198)	$ (12,481)	$ (26,831)	$ (28,879)	$ (73,520)
Net loss per share from continuing operations (USD per share)	$ (0.12)	$ (0.04)	$ (0.13)	$ (0.17)	$ (0.16)	$ (0.05)	$ (0.08)	$ (0.19)
Net loss from discontinued operations per share basic and diluted (USD per share)					$ 0	$ 0	$ 0	$ (0.03)	$ 0	$ (0.03)	$ (0.21)
Neighborhood Diabetes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of taxes										$ (1,669)	$ (11,918)
Impairment and other charges					$ 6,100						$ 9,100

Schedule II - Valuation and Q98

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 2,911	$ 4,454	$ 5,837
Additions Charged to Costs and Expenses	1,923	2,069	1,184
Deductions	2,293	3,612	2,567
Balance at End of Period	2,541	2,911	4,454
Deferred tax valuation allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	191,922	193,405	165,020
Additions Charged to Costs and Expenses	14,232	7,599	28,418
Deductions	78,227	9,082	33
Balance at End of Period	$ 127,927	$ 191,922	$ 193,405