Align Technology (ALGN) 10-Q 1 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 26, 2018
Document Documentand Entity Information [Abstract]
Trading Symbol	ALGN
Entity Registrant Name	ALIGN TECHNOLOGY INC
Entity Central Index Key	1,097,149
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		79,984,381

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net revenues	$ 505,289	$ 385,267	$ 1,432,472	$ 1,052,090
Cost of net revenues	133,508	92,779	367,701	253,060
Gross profit	371,781	292,488	1,064,771	799,030
Operating expenses:
Selling, general and administrative	213,873	169,524	625,585	483,636
Research and development	32,700	24,201	93,095	71,389
Total operating expenses	246,573	193,725	718,680	555,025
Income from operations	125,208	98,763	346,091	244,005
Interest income	2,234	1,826	6,327	4,462
Other income (expense), net	(837)	1,924	(7,759)	4,145
Net income before provision for income taxes and equity in losses of investee	126,605	102,513	344,659	252,612
Provision for income taxes	24,601	18,344	35,206	26,508
Equity in losses of investee, net of tax	1,132	1,614	6,610	4,950
Net income	$ 100,872	$ 82,555	$ 302,843	$ 221,154
Net income per share:
Basic (in usd per share)	$ 1.26	$ 1.03	$ 3.78	$ 2.76
Diluted (in usd per share)	$ 1.24	$ 1.01	$ 3.71	$ 2.71
Shares used in computing net income per share:
Basic (in shares)	80,111	80,163	80,122	80,086
Diluted (in shares)	81,359	81,789	81,538	81,757

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 100,872	$ 82,555	$ 302,843	$ 221,154
Net change in foreign currency translation adjustment	(1,756)	884	(1,473)	1,624
Change in unrealized gains (losses) on investments, net of tax	117	60	174	102
Other comprehensive (loss) income	(1,639)	944	(1,299)	1,726
Comprehensive income	$ 99,233	$ 83,499	$ 301,544	$ 222,880

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 420,860	$ 449,511
Marketable securities, short-term	184,297	272,031
Accounts receivable, net of allowance for doubtful accounts of $2,611 and $5,814, respectively	420,276	324,189
Inventories	48,858	31,688
Prepaid expenses and other current assets	149,891	80,948
Total current assets	1,224,182	1,158,367
Marketable securities, long-term	8,091	39,948
Property, plant and equipment, net	491,630	348,793
Equity method investments	47,996	54,606
Goodwill and intangible assets, net	83,607	89,068
Deferred tax assets	47,435	49,334
Other assets	25,464	43,893
Total assets	1,928,405	1,784,009
Current liabilities:
Accounts payable	43,065	36,776
Accrued liabilities	219,035	195,562
Deferred revenues	356,109	267,713
Total current liabilities	618,209	500,051
Income tax payable	95,655	114,091
Other long-term liabilities	21,558	15,579
Total liabilities	735,422	629,721
Commitments and contingencies (Notes 8 and 9)
Stockholders' equity:
Preferred stock, $0.0001 par value (5,000 shares authorized; none issued)	0	0
Common stock, $0.0001 par value (200,000 shares authorized; 79,983 and 80,040 issued and outstanding, respectively)	8	8
Additional paid-in capital	865,271	886,435
Accumulated other comprehensive income (loss), net	(728)	571
Retained earnings	328,432	267,274
Total stockholders’ equity	1,192,983	1,154,288
Total liabilities and stockholders’ equity	$ 1,928,405	$ 1,784,009

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable, allowance for doubtful accounts	$ 2,611	$ 5,814
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	79,983	80,040
Common stock, shares outstanding	79,983	80,040

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 302,843	$ 221,154
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred taxes	2,047	(5,481)
Depreciation and amortization	38,185	26,715
Stock-based compensation	51,918	44,024
Equity in losses of investee	6,610	4,950
Other non-cash operating activities	11,363	9,432
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	(89,843)	(84,437)
Inventories	(17,192)	(10,709)
Prepaid expenses and other assets	(47,775)	(5,848)
Accounts payable	5,042	4,220
Accrued and other long-term liabilities	(25,436)	18,752
Long-term income tax payable	(18,435)	243
Deferred revenues	94,059	53,198
Net cash provided by operating activities	313,386	276,213
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions, net of cash acquired	0	(8,953)
Purchase of property, plant and equipment	(169,033)	(126,150)
Purchase of marketable securities	(150,022)	(356,928)
Proceeds from maturities of marketable securities	259,870	260,487
Purchases of investments in privately held companies	(5,000)	(12,764)
Proceeds from sales of marketable securities	9,560	32,291
Loan advances to equity investee	0	(23,000)
Loan repayment from equity investee	30,000	6,000
Other investing activities	604	(2,767)
Net cash used in investing activities	(24,021)	(231,784)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	16,607	13,850
Common stock repurchases	(250,002)	(53,793)
Employees’ taxes paid upon the vesting of restricted stock units	(81,756)	(39,093)
Net cash used in financing activities	(315,151)	(79,036)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	(2,890)	4,806
Net decrease in cash, cash equivalents, and restricted cash	(28,676)	(29,801)
Cash, cash equivalents, and restricted cash at beginning of the period	450,125	393,019
Cash, cash equivalents, and restricted cash at end of the period	421,449	363,218
SUPPLEMENTAL CASH FLOW INFORMATION:
Accounts payable or accrued liabilities related to property, plant and equipment	24,281	21,992
Conversion of convertible notes receivable into equity securities	$ 4,862	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements have been prepared by Align Technology, Inc. (“we”, “our”, or “Align”) in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) and contains all adjustments, including normal recurring adjustments, necessary to state fairly our results of operations for the three and nine months ended September 30, 2018 and 2017 , our comprehensive income for the three and nine months ended September 30, 2018 and 2017 , our financial position as of September 30, 2018 and our cash flows for the nine months ended September 30, 2018 and 2017 . The Condensed Consolidated Balance Sheet as of December 31, 2017 was derived from the December 31, 2017 audited financial statements and have been recast to reflect the adoption of accounting standards as described below. It does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S.”). During the first quarter of fiscal year 2018, we adopted the Accounting Standards Codification (“ASC”) 606, “ Revenues from Contracts with Customers, ” using the full retrospective method and Accounting Standards Update (“ASU”) 2016-18, “ Statement of Cash Flows - Restricted Cash, ” on a retrospective basis. The Condensed Consolidated Balance Sheet as of December 31, 2017 and the Condensed Consolidated Statement of Cash Flow for the nine months ended September 30, 2017 have been recast to comply with the adoption of these standards. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or any other future period, and we make no representations related thereto. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A and 8, respectively, in our Annual Report on Form 10-K for the year ended December 31, 2017 . Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles (“GAAP”) in the U.S. requires our management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. On an ongoing basis, we evaluate our estimates, including those related to the fair values of financial instruments, valuation of investments in privately held companies, useful lives of intangible assets and property and equipment, revenue recognition, stock-based compensation, long-lived assets and goodwill, income taxes and contingent liabilities, among others. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Significant Accounting Policies Our significant accounting policies are described in Note 1 “Summary of Significant Accounting Policies” of the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K. Significant changes to the Revenue Recognition policy and Investments in Privately Held Companies policy are discussed below: Revenue Recognition Our revenues are derived primarily from the sale of aligners, scanners, and services from our Clear Aligner and Scanner segments. We enter into sales contracts that may consist of multiple distinct performance obligations where certain performance obligations of the sales contract are not delivered in one reporting period. We measure and allocate revenues according to ASC 606-10, “ Revenues from Contracts with Customers. ” We identify a performance obligation as distinct if both of the following criteria are true: the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. Determining the standalone selling price (“SSP”) and allocation of consideration from a contract to the individual performance obligations, and the appropriate timing of revenue recognition, is the result of significant qualitative and quantitative judgments. Management considers a variety of factors such as historical sales, usage rates, costs, and expected margin, which may vary over time depending upon the unique facts and circumstances related to each performance obligation in making these estimates. While changes in the allocation of the SSP between performance obligations will not affect the amount of total revenues recognized for a particular contract, any material changes could impact the timing of revenue recognition, which would have a material effect on our financial position and result of operations. This is because the contract consideration is allocated to each performance obligation, delivered or undelivered, at the inception of the contract based on the SSP of each distinct performance obligation. Clear Aligner We enter into contracts (“treatment plan(s)”) that involve multiple future performance obligations. Invisalign Comprehensive, Invisalign Full, Invisalign Teen, Invisalign First, Invisalign Lite, Invisalign Express and Invisalign Assist products include optional additional aligners at no charge for a certain period of time, from one to five years after initial shipment, and Invisalign Go includes optional additional aligners at no charge for a period of up to two years after initial shipment. We determined that our treatment plans comprise the following performance obligations that also represent distinct deliverables: initial aligners, additional aligners, case refinement, and replacement aligners. We elected to take the practical expedient to consider shipping and handling costs as activities to fulfill the performance obligation. We allocate revenues for each treatment plan based on each unit’s SSP and recognize the revenues upon shipment, as the customers obtain physical possession and we have enforceable rights to payment. As we collect most consideration upfront, we considered whether a significant financing component exists; however, as the delivery of the performance obligations are at the customer’s discretion, we concluded that no significant financing component exists. Scanner We sell intraoral scanners and computer-aided design/computer-aided manufacturing (“CAD/CAM”) services through both our direct sales force and distribution partners. The intraoral scanner sales price includes one year of warranty and unlimited scanning services. The customer may also select, for additional fees, extended warranty and unlimited scanning services for periods beyond the initial year. When intraoral scanners are sold with an unlimited scanning service agreement and/or extended warranty, we allocate revenues based on each element’s SSP. We estimate the SSP of each element, taking into consideration historical prices as well as our discounting strategies. Revenues are then recognized over time as the monthly services are rendered and upon shipment for the scanner, as that is when we deem the customer to have obtained control. Most consideration is collected upfront and in cases where there are payment plans, consideration is collected by the one year mark and therefore, there are no significant financing components. Warranties For both Clear Aligner and Scanner segments, we offer an assurance warranty which provides the customer assurance that the product will function as the parties intended because it complies with agreed-upon specifications, and thus is not treated as a separate performance obligation and will continue to be accrued in accordance with the Financial Accounting Standards Board (“FASB”) guidance on guarantees. Volume Discounts In certain situations, we offer promotions in which the discount will increase depending upon the volume purchased over time. We concluded that in these situations, the promotions can represent either variable consideration or options, depending upon the specifics of the promotion. In the event the promotion contains an option, the option is considered a material right and, therefore, included in the accounting for the initial arrangement. We estimate the average anticipated discount over the lifetime of the promotion or contract, and apply that discount to each unit as it is sold. On a quarterly basis, we review our estimates and, if needed, updates are made and changes are applied prospectively. Costs to Obtain a Contract We offer a variety of commission plans to our salesforce; each plan has multiple components. To match the costs to obtain a contract to the associated revenue, we evaluate the individual components and capitalize the eligible components, recognizing the costs over the treatment period. Unfulfilled Performance Obligations for Clear Aligners and Scanners Our unfilled performance obligations as of September 30, 2018 and the estimated revenues expected to be recognized in the future related to these performance obligations are $380.7 million . This includes performance obligations from the Clear Aligner segment, primarily the shipment of additional aligners, which are fulfilled over one to five years, and performance obligations from the iTero scanner segment, primarily contracted deliveries of additional scanners and support, which are fulfilled over one to five years. The estimate includes both product and service unfulfilled performance obligations and the time range reflects our best estimate of when we will transfer control to the customer and may change based on customer usage patterns, timing of shipments, readiness of customers’ facilities for installation, and manufacturing availability. Contract Balances The timing of revenue recognition results in deferred revenues being recognized on the Condensed Consolidated Balance Sheet. For both aligners and scanners, we usually collect the total consideration owed prior to all performance obligations being performed and payment terms vary from net 30 to net 180 days. Contract liabilities are recorded as deferred revenue balances, which are generated based upon timing of invoices and recognition patterns, not payments. If the revenue recognition exceeds the billing, the exceeded amount is considered unbilled receivable and a contract asset. Conversely, if the billing occurs prior to the revenue recognition, the amount is considered deferred revenue and a contract liability. Investments in Privately Held Companies Investments in privately held companies in which we can exercise significant influence but do not own a majority equity interest or otherwise control are accounted for under ASC 323, “ Investments—Equity Method and Joint Ventures. ” Equity securities qualified as equity method investments are reported on our Condensed Consolidated Balance Sheet as a single amount, and we record our share of their operating results within equity in losses of investee, net of tax, in our Condensed Consolidated Statement of Operations. Investments in privately held companies in which we cannot exercise significant influence and do not own a majority equity interest or otherwise control are accounted for under ASC 321, “ Investments—Equity Securities. ” The equity securities without readily determinable fair values are recorded at cost and adjusted for impairments and observable price changes with a same or similar security from the same issuer (“Measurement Alternative”). Equity securities under ASC 321 are reported on our Condensed Consolidated Balance Sheet as other assets, and we record a change in carrying value of our equity securities, if any, in other income (expense), net in our Condensed Consolidated Statement of Operations. Equity securities are evaluated for impairment as events or circumstances indicate that there is an other-than-temporary loss in value. The decrease in value is recognized in the period the impairment occurs and recorded in other income (expense), net in the Condensed Consolidated Statement of Operations. Recent Accounting Pronouncements (i) New Accounting Updates Recently Adopted In May 2014, the FASB released ASU 2014-09, “ Revenue from Contracts with Customers, ” (Topic 606) to supersede nearly all existing revenue recognition guidance under GAAP. The core principle of the standard is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for the goods or services. We adopted the guidance in the first quarter of fiscal year 2018 by applying the full retrospective method. The impact of adoption was primarily related to the Clear Aligner segment. Our disaggregation of revenues can be found in Note 14 “Segments and Geographical Information.” We elected to take the practical expedient to exclude from the transaction price all taxes assessed by a governmental authority. In preparation for adoption of the standard, we have reviewed and, where necessary, implemented additional key system functionalities and internal controls to enable the preparation of financial information. Prior periods have been retrospectively adjusted, and we recognized cumulative effect of adopting the guidance as an adjustment to our opening balance of retained earnings as of January 1, 2016. The adoption of ASU 2014-09 did not have a material impact on our Condensed Consolidated Statements of Operations, Condensed Consolidated Statements of Comprehensive Income or Condensed Consolidated Statements of Cash Flows for the historical periods presented in the Item 1 Financial Statements section. Consolidated Balance Sheet line items, which reflect the adoption of the ASU 2014-09 are as follows (in thousands): December 31, 2017 As Previously Reported Adjustment As Adjusted Asset Accounts: Accounts receivable, net $ 322,825 $ 1,364 $ 324,189 Deferred tax assets 50,059 (725 ) 49,334 Other assets 38,379 5,514 43,893 Liability and Stockholders’ Equity Accounts: Accrued liabilities $ 194,198 $ 1,364 $ 195,562 Deferred revenues 266,842 871 267,713 Retained earnings 263,356 3,918 267,274 In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments,” which clarifies the presentation and classification of certain cash receipts and cash payments in the statements of cash flows. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017. We adopted the standard in the first quarter of fiscal year 2018 on a retrospective basis, and it did not have an impact on our Condensed Consolidated Statements of Cash Flows. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows—Restricted Cash,” which provides guidance to address the classification and presentation of changes in restricted cash in the statements of cash flows . The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 on a retrospective basis. We adopted the guidance in the first quarter of fiscal year 2018 on a retrospective basis and presented the changes in the total of cash, cash equivalents, and restricted cash in the Condensed Consolidated Statements of Cash Flows. Condensed Consolidated Statement of Cash Flows line items, which reflect the adoption of the ASU 2016-18, are as follows (in thousands): Nine Months Ended September 30, 2017 As Previously Reported Adjustment As Adjusted Cash Flows from Investing Activities Other investing activities $ 397 $ (3,164 ) $ (2,767 ) Net cash used in investing activities (228,620 ) (3,164 ) (231,784 ) Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash 4,781 25 4,806 Net decrease in cash, cash equivalents, and restricted cash (26,662 ) (3,139 ) (29,801 ) Cash, cash equivalents, and restricted cash at beginning of the period 389,275 3,744 393,019 Cash, cash equivalents, and restricted cash at end of the period $ 362,613 $ 605 $ 363,218 In May 2017, the FASB issued ASU 2017-09, “ Compensation — Stock Compensation (Topic 718): Scope of Modification Accounting,” to clarify when to account for a change to the terms or conditions of a share-based payment award as a modification. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 on a prospective basis. We adopted the standard in the first quarter of fiscal year 2018 on a prospective basis which did not have an impact on our condensed consolidated financial statements and related disclosures. (ii) Recent Accounting Updates Not Yet Effective In February 2016, the FASB issued ASU 2016-02, “ Leases ” (Topic 842) to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The updated guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. In July 2018, the FASB issued ASU 2018-11, “ Leases- Targeted Improvements, ” which p rovides an additional transition method by allowing entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings. We plan to adopt the standard in the first quarter of fiscal year 2019 by electing the transition method issued in ASU 2018-11 and the package of practical expedients available in the standard. In addition, we are in the process of implementing changes to our systems, processes and controls and are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements. We expect the adoption will have a material increase in assets and liabilities on our consolidated balance sheet. In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments - Credit Losses ” (Topic 326) . The FASB issued this update to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments in this update replace the existing guidance of incurred loss impairment methodology with an approach that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The updated guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption of the update is permitted in fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” to simplify the subsequent measurement of goodwill by eliminating step two from the goodwill impairment test. Under the amendments, an entity will recognize an impairment charge for the amount by which the carrying value exceeds the fair value. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 on a prospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In February 2018, the FASB issued ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” which gives entities the option to reclassify to retained earnings the tax effects resulting from the U.S. Tax Cuts and Jobs Act (the “TCJA”) related to items in accumulated other comprehensive income. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2018 on a retrospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-13, “ Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement,” to modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement . The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 on a prospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our related disclosures. In August 2018, the FASB issued ASU 2018-15, “ Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” to clarify the guidance on the costs of implementing a cloud computing hosting arrangement that is a service contract. Under the amendments, the entity is required to follow the guidance in Subtopic 350-40, Internal-Use Software , to determine which implementation costs under the service contract to be capitalized as an asset and which costs to expense. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 either on a retrospective or prospectively basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

Investments and Fair Value Meas

Investments and Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Investments and Fair Value Measurements	Investments and Fair Value Measurements Marketable Securities As of September 30, 2018 and December 31, 2017 , the estimated fair value of our short-term and long-term marketable securities, classified as available for sale, are as follows (in thousands): Short-term September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 24,675 $ — $ — $ 24,675 Corporate bonds 75,461 1 (94 ) 75,368 U.S. government agency bonds 11,665 — (31 ) 11,634 U.S. government treasury bonds 72,622 — (22 ) 72,600 Certificates of deposit 20 — — 20 Total marketable securities, short-term $ 184,443 $ 1 $ (147 ) $ 184,297 Long-term September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. government agency bonds $ 7,035 $ — $ (74 ) $ 6,961 Corporate bonds 1,127 3 — 1,130 Total marketable securities, long-term $ 8,162 $ 3 $ (74 ) $ 8,091 Short-term December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 58,503 $ — $ (1 ) $ 58,502 Corporate bonds 145,728 3 (174 ) 145,557 U.S. government agency bonds 3,013 — (7 ) 3,006 U.S. government treasury bonds 60,650 — (70 ) 60,580 Certificates of deposit 4,386 — — 4,386 Total marketable securities, short-term $ 272,280 $ 3 $ (252 ) $ 272,031 Long-term December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. government agency bonds $ 15,023 $ — $ (68 ) $ 14,955 Corporate bonds 25,067 2 (76 ) 24,993 Total marketable securities, long-term $ 40,090 $ 2 $ (144 ) $ 39,948 Cash equivalents are not included in the table above as the gross unrealized gains and losses are not material. We have no short-term or long-term investments that have been in a continuous material unrealized loss position for greater than twelve months as of September 30, 2018 and December 31, 2017 . Amounts reclassified to earnings from accumulated other comprehensive income (loss), net related to unrealized gains or losses were not material for the three and nine months ended September 30, 2018 and 2017. For the three and nine months ended September 30, 2018 and 2017, realized gains or losses were not material. Our fixed-income securities investment portfolio consists of investments that have a maximum effective maturity of 40 months on any individual security. The securities that we invest in are generally deemed to be low risk based on their credit ratings from the major rating agencies. The longer the duration of these securities, the more susceptible they are to changes in market interest rates and bond yields. As interest rates increase, those securities purchased at a lower yield show a mark-to-market unrealized loss. The unrealized losses are due primarily to changes in credit spreads and interest rates. We expect to realize the full value of all these investments upon maturity or sale. The weighted average remaining duration of these securities was approximately three months and six months as of September 30, 2018 and December 31, 2017 , respectively. As the carrying value approximates the fair value for our short-term and long-term marketable securities shown in the tables above, the following table summarizes the fair value of our short-term and long-term marketable securities classified by contractual maturity as of September 30, 2018 and December 31, 2017 (in thousands): September 30, December 31, One year or less $ 184,297 $ 272,031 Due in greater than one year 8,091 39,948 Total available for sale short-term and long-term marketable securities $ 192,388 $ 311,979 Investments in Privately Held Companies Our investments in privately held companies as of September 30, 2018 and December 31, 2017 are as follows (in thousands): September 30, December 31, Equity securities under the equity method investment 1 $ 47,996 $ 54,606 Equity securities without readily determinable fair values 2 $ 9,862 $ — 1 Refer to Note 4 “Equity Method Investments” of the Notes to Condensed Consolidated Financial Statements for more information 2 In April 2018, $4.9 million of convertible short term notes receivable (recurring Level 3 investment) was converted into equity securities as a result of qualified financing secured by the private company in accordance with ASC 321, “Investments—Equity Securities.” The equity securities issued upon conversion are reported as a nonrecurring investment within other assets in our Condensed Consolidated Balance Sheet. During the three and nine months ended September 30, 2018 , there were no fair value adjustments to equity securities without readily determinable fair values. Fair Value Measurements We measure the fair value of financial assets as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We use the GAAP fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. This hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The three levels of inputs that may be used to measure fair value: Level 1 — Quoted (unadjusted) prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability. We obtain fair values for our Level 2 investments. Our custody bank and asset managers independently use professional pricing services to gather pricing data which may include quoted market prices for identical or comparable financial instruments, or inputs other than quoted prices that are observable either directly or indirectly, and we are ultimately responsible for these underlying estimates. Level 3 — Unobservable inputs to the valuation methodology that are supported by little or no market activity and that are significant to the measurement of the fair value of the assets or liabilities. Level 3 assets and liabilities include those whose fair value measurements are determined using pricing models, discounted cash flow methodologies or similar valuation techniques, as well as significant management judgment or estimation. The following tables summarize our financial assets measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017 (in thousands): Description Balance as of September 30, 2018 Level 1 Level 2 Cash equivalents: Money market funds $ 256,689 $ 256,689 $ — Commercial paper 6,883 — 6,883 Corporate bonds 2,014 — 2,014 Short-term investments: Commercial paper 24,675 — 24,675 Corporate bonds 75,368 — 75,368 U.S. government agency bonds 11,634 — 11,634 U.S. government treasury bonds 72,600 72,600 — Certificates of deposit 20 — 20 Long-term investments: U.S. government agency bonds 6,961 — 6,961 Corporate bonds 1,130 — 1,130 Prepaid expenses and other current assets: Israeli funds 3,143 — 3,143 $ 461,117 $ 329,289 $ 131,828 Description Balance as of December 31, 2017 Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 253,155 $ 253,155 $ — $ — Commercial paper 7,246 — 7,246 — Corporate bonds 2,016 — 2,016 — Short-term investments: Commercial paper 58,502 — 58,502 — Corporate bonds 145,557 — 145,557 — U.S. government agency bonds 3,006 — 3,006 — U.S. government treasury bonds 60,580 60,580 — — Certificates of deposit 4,386 — 4,386 — Long-term investments: U.S. government agency bonds 14,955 — 14,955 — Corporate bonds 24,993 — 24,993 — Prepaid expenses and other current assets: Israeli funds 3,075 — 3,075 — Short-term notes receivable 4,476 — — 4,476 $ 581,947 $ 313,735 $ 263,736 $ 4,476 Derivative Financial Instruments In March 2018, we began entering into foreign currency forward contracts to minimize the short-term impact of foreign currency exchange rate fluctuations on certain trade and intercompany receivables and payables. These forward contracts are classified within Level 2 of the fair value hierarchy. The gains from the settlement of foreign currency forward contracts during the three and nine months ended September 30, 2018 were $2.3 million and $7.7 million , respectively. As of September 30, 2018 , the fair value of foreign exchange forward contracts outstanding was not material. The following table presents the gross notional value of all our foreign exchange forward contracts outstanding as of September 30, 2018 (in thousands): September 30, 2018 Local Currency Amount Notional Contract Amount (USD) Euro €61,000 $ 70,992 Chinese Yuan ¥330,000 47,882 Canadian Dollar C$28,000 21,653 British Pound £13,000 16,966 Japanese Yen ¥1,700,000 14,985 Brazilian Real R$55,500 13,821 Australian Dollar A$2,900 2,097 $ 188,396

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Inventories Inventories consist of the following (in thousands): September 30, December 31, Raw materials $ 23,395 $ 12,721 Work in process 11,090 12,157 Finished goods 14,373 6,810 Total inventories $ 48,858 $ 31,688 Other Assets Other assets consist of the following (in thousands): September 30, December 31, Capitalized commissions $ 8,651 $ 5,515 Equity securities 9,862 — Security deposits 4,259 3,557 Loan receivable from equity investee — 30,000 Other long-term assets 2,692 4,821 Total other assets $ 25,464 $ 43,893 Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, December 31, Accrued payroll and benefits $ 102,109 $ 103,004 Accrued expenses 36,110 27,318 Accrued fixed assets 17,765 11,362 Accrued warranty 8,026 5,929 Accrued professional fees 7,774 6,316 Accrued sales rebate 7,765 11,209 Accrued customer credits 7,618 5,373 Accrued sales tax and value added tax 6,734 5,503 Accrued sales return reserve 1 5,876 1,364 Accrued income taxes 4,111 12,405 Other accrued liabilities 15,147 5,779 Total accrued liabilities $ 219,035 $ 195,562 1 December 31, 2017 balance has been reclassified from accounts receivable, net to reflect the adoption of ASU 2014-09 ( Refer to Note 1 “Summary of Significant Accounting Policies” of the Notes to Condensed Consolidated Financial Statements for more information). Warranty We regularly review the balance for accrued warranty and update based on historical warranty trends. Actual warranty costs incurred have not materially differed from those accrued; however, future actual warranty costs could differ from the estimated amounts. Warranty accrual as of September 30, 2018 and 2017 consists of the following activity (in thousands): Nine Months Ended 2018 2017 Balance at beginning of period $ 5,929 $ 3,841 Charged to cost of revenues 10,874 5,201 Actual warranty expenditures (8,777 ) (3,987 ) Balance at end of period $ 8,026 $ 5,055 Deferred Revenues Deferred revenues consist of the following (in thousands): September 30, December 31, Deferred revenues - current $ 356,109 $ 267,713 Deferred revenues - long-term 1 11,739 4,588 1 Included in other long-term liabilities within our Condensed Consolidated Balance Sheets During the three months ended September 30, 2018 and September 30, 2017 , we recognized $505.3 million and $385.3 million of revenue, respectively, of which $125.6 million and $74.0 million was included in the deferred revenues balance at December 31, 2017 and December 31, 2016 , respectively. During the nine months ended September 30, 2018 and September 30, 2017 , we recognized $1.4 billion and $1.1 billion of revenue, respectively, of which $313.4 million and $186.8 million was included in the deferred revenues balance at December 31, 2017 and December 31, 2016 , respectively.

Equity Method Investments

Equity Method Investments	9 Months Ended
	Sep. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments On July 25, 2016, we acquired a 17% equity interest, on a fully diluted basis, in SmileDirectClub, LLC (“SDC”) for $46.7 million . The investment is accounted for under an equity method investment and the investee, SDC, is considered a related party. The investment is reported in our Condensed Consolidated Balance Sheets under equity method investments, and we record our proportional share of SDC’s losses within equity in losses of investee, net of tax, in our Condensed Consolidated Statement of Operations. On July 24, 2017, we purchased an additional 2% equity interest in SDC for $12.8 million . As of September 30, 2018 and December 31, 2017 , the balance of our equity method investments was $48.0 million and $54.6 million , respectively. Concurrently with the investment on July 25, 2016, we also entered into a supply agreement with SDC to manufacture clear aligners for SDC’s doctor-led, at-home program for simple teeth straightening. The term of the supply agreement expires on December 31, 2019. We commenced supplying aligners to SDC in October 2016. The sale of aligners to SDC and the income from the supply agreement are reported in our Clear Aligner business segment. We eliminate unrealized profit on outstanding intercompany transactions. As of September 30, 2018 and December 31, 2017 , the balance of accounts receivable due from SDC was $12.5 million and $14.3 million , respectively. For the three months ended September 30, 2018 and 2017 , net revenues recognized from SDC was $8.1 million and $10.6 million , respectively, and for the nine months ended September 30, 2018 and 2017 , net revenues recognized from SDC was $22.0 million and $14.2 million , respectively. On July 25, 2016, we entered into a Loan and Security Agreement (the “Loan Agreement”) with SDC and amended on July 24, 2017 where we agreed to provide SDC a loan of up to $30.0 million in one or more advances. On February 7, 2018, $30.0 million of outstanding loan advances and related accrued interest were repaid in full, and the Loan Agreement was terminated ( Refer to Note 8 “Legal Proceedings” of the Notes to Condensed Consolidated Financial Statements for SDC legal proceedings discussion).

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Combinations	Business Combinations During the first quarter of 2017, we completed the acquisitions of certain of our distributors for the total cash consideration of approximately $9.5 million including cash acquired. We recorded $1.9 million of net tangible liabilities, $8.2 million of identifiable intangible assets and $3.2 million of goodwill. The goodwill is primarily related to the benefit we expect to obtain from direct sales as we believe that the transition from our distributor arrangements to a direct sales model will increase our net revenues in the region as we will experience higher average sales prices (“ASP”) compared to our discounted ASP under the distribution agreements. The goodwill is not deductible for tax purposes. Pro forma results of operations for these acquisitions have not been presented as they were not material to our results of operations, either individually or in aggregate, for the nine months ended September 30, 2017 .

Goodwill and Long-lived Assets

Goodwill and Long-lived Assets	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill The change in the carrying value of goodwill for the nine months ended September 30, 2018 , all attributable to our Clear Aligner reporting unit, is as follows (in thousands): Total Balance as of December 31, 2017 $ 64,614 Adjustments 1 (542 ) Balance as of September 30, 2018 $ 64,072 1 The adjustments to goodwill during the period were a result of foreign currency translation During the fourth quarter of fiscal 2017, we performed the annual goodwill impairment testing and found no impairment as the fair value of our Clear Aligner reporting unit was significantly in excess of the carrying value. Intangible Long-Lived Assets Acquired intangible long-lived assets are being amortized as follows (in thousands): Weighted Average Amortization Period (in years) Gross Carrying Amount as of Accumulated Amortization Accumulated Impairment Loss Net Carrying Trademarks 15 $ 7,100 $ (1,873 ) $ (4,179 ) $ 1,048 Existing technology 13 12,600 (5,127 ) (4,328 ) 3,145 Customer relationships 11 33,500 (16,078 ) (10,751 ) 6,671 Reacquired rights 3 7,500 (3,604 ) — 3,896 Patents 8 6,796 (2,126 ) — 4,670 Other 2 618 (513 ) — 105 Total intangible assets $ 68,114 $ (29,321 ) $ (19,258 ) $ 19,535 Weighted Average Amortization Period (in years) Gross Carrying Amount as of December 31, 2017 Accumulated Amortization Accumulated Impairment Loss Net Carrying Value as of December 31, 2017 Trademarks 15 $ 7,100 $ (1,769 ) $ (4,179 ) $ 1,152 Existing technology 13 12,600 (4,704 ) (4,328 ) 3,568 Customer relationships 11 33,500 (14,681 ) (10,751 ) 8,068 Reacquired rights 3 7,500 (1,356 ) — 6,144 Patents 8 6,798 (1,504 ) — 5,294 Other 2 618 (390 ) — 228 Total intangible assets $ 68,116 $ (24,404 ) $ (19,258 ) $ 24,454 The total estimated annual future amortization expense for these acquired intangible assets as of September 30, 2018 is as follows (in thousands): Fiscal Year Ending December 31, Amortization Remainder of 2018 $ 1,571 2019 6,171 2020 3,854 2021 3,388 2022 2,116 Thereafter 2,435 Total $ 19,535 Amortization for both the three months ended September 30, 2018 and 2017 was $1.5 million and amortization for the nine months ended September 30, 2018 and 2017 was $4.5 million and $4.7 million , respectively.

Credit Facilities

Credit Facilities	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Credit Facilities	Credit Facilities On February 27, 2018, we entered into a new credit facility for a $200.0 million revolving line of credit, with a $50.0 million letter of credit sublimit, and a maturity date of February 27, 2021, replacing the existing credit facility which provided for a $50.0 million revolving line of credit with a $10.0 million letter of credit. The credit facility requires us to comply with specific financial conditions and performance requirements. The loans bear interest, at our option, at either a rate based on the reserve adjusted LIBOR for the applicable interest period or a base rate, in each case plus a margin. The base rate is the highest of the credit facility’s publicly announced prime rate, the federal funds rate plus 0.50% and one month LIBOR plus 1.0% . The margin ranges from 1.25% to 1.75% for LIBOR loans and 0.25% to 0.75% for base rate loans. Interest on the loans is payable quarterly in arrears with respect to base rate loans and at the end of an interest period (and at three month intervals if the interest period exceeds three months) in the case of LIBOR loans. Principal, together with accrued and unpaid interest, is due on the maturity date. As of September 30, 2018 , we had no outstanding borrowings under this credit facility and were in compliance with the conditions and performance requirements.

Legal Proceedings (Notes)

Legal Proceedings (Notes)	9 Months Ended
	Sep. 30, 2018
Legal Proceedings [Abstract]
Legal Proceedings	Legal Proceedings Patent Infringement Lawsuit On November 14, 2017, Align filed six patent infringement lawsuits asserting 26 patents against 3Shape A/S, a Danish corporation, and a related U.S. corporate entity, asserting that 3Shape’s Trios intraoral scanning system and Dental System software infringe Align patents. Align filed two Section 337 complaints with the U.S. International Trade Commission (“ITC”) alleging that 3Shape violates U.S. trade laws by selling for importation and importing its infringing Trios intraoral scanning system and Dental System software. Align’s ITC complaints seek cease and desist orders and exclusion orders prohibiting the importation of 3Shape’s Trios scanning system and Dental System software products into the U.S. Align also filed four separate complaints in the United States District Court for the District of Delaware alleging patent infringement by 3Shape’s Trios intraoral scanning system and Dental System software. All of these district court complaints seek monetary damages and injunctive relief against further infringement. SDC Dispute On April 5, 2018, SDC Financial LLC, SmileDirectClub LLC, and the Members of SDC Financial LLC other than Align (collectively, the "SDC Entities") initiated proceedings that seek, among other forms of relief, to preliminarily and permanently enjoin all activities related to the Invisalign Experience program, require Align to close the existing Invisalign locations, prohibit Align from opening any additional locations, and allow the SDC Entities to exercise a right to repurchase all of Align's SDC Financial LLC membership interests for a purchase price equal to the current capital account balance. On June 29, 2018, the Chancery Court for Davidson County, Tennessee, denied the SDC Entities’ request for a temporary injunction to prevent Align from opening additional Invisalign locations. Align continues to dispute the allegations that it has breached its obligations to the SDC Entities under applicable law and will oppose and vigorously defend itself at the arbitration proceedings currently scheduled for December 2018. This dispute does not impact Align’s existing supply agreement with SDC which remains in place through 2019 and includes a minimum volume commitment. We are currently unable to predict the outcome of this dispute and therefore cannot determine the likelihood of loss, if any, nor estimate a range of possible loss. In addition, in the course of Align’s operations, Align is involved in a variety of claims, suits, investigations, and proceedings, including actions with respect to intellectual property claims, patent infringement claims, government investigations, labor and employment claims, breach of contract claims, tax, and other matters. Regardless of the outcome, these proceedings can have an adverse impact on us because of defense costs, diversion of management resources, and other factors. Although the results of complex legal proceedings are difficult to predict and Align’s view of these matters may change in the future as litigation and events related thereto unfold; Align currently does not believe that these matters, individually or in the aggregate, will materially affect Align’s financial position, results of operations or cash flows.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases As of September 30, 2018 , minimum future lease payments for non-cancelable operating leases are as follows (in thousands): Fiscal Year Ending December 31, Operating Leases Remainder of 2018 $ 4,839 2019 19,131 2020 15,988 2021 14,386 2022 12,026 Thereafter 25,769 Total minimum future lease payments $ 92,139 Sublease income is not material and excluded from the table above. Other Commitments On July 25, 2016, we entered into a Loan and Security Agreement (the “Loan Agreement”) with SDC and subsequently amended on July 24, 2017 to provide a loan of up to $30.0 million in one or more advances to SDC (the “Loan Facility”). On February 7, 2018, $30.0 million of outstanding advances and related accrued interest were repaid in full, and the Loan Agreement was terminated ( Refer to Note 4 “Equity Method Investments” of the Notes to Condensed Consolidated Financial Statements for more information on our investments in SDC). On November 27, 2017, we entered into a Purchase Agreement with one of our existing single source suppliers. Under the terms of the original agreement, we are required to purchase a minimum approximately $305.2 million of aligner materials over the next four years. On May 29, 2018, we entered into an amendment to the Purchase Agreement with the existing single source supplier to increase the original term of the agreement to five years and total minimum purchase amount to approximately $425.9 million . Off-Balance Sheet Arrangements As of September 30, 2018 , we had no material off-balance sheet arrangements that have, or are reasonably likely to have, a current or future material effect on our consolidated financial condition, results of operations, liquidity, capital expenditures or capital resources other than certain items disclosed in Note 9 “Commitments and Contingencies” of the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K. Indemnification Provisions In the normal course of business to facilitate transactions in our services and products, we indemnify certain parties: customers, vendors, lessors, and other parties with respect to certain matters, including, but not limited to, services to be provided by us and intellectual property infringement claims made by third parties. In addition, we have entered into indemnification agreements with our directors and our executive officers that will require us, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. Several of these agreements limit the time within which an indemnification claim can be made and the amount of the claim. It is not possible to make a reasonable estimate of the maximum potential amount under these indemnification agreements due to the unique facts and circumstances involved in each particular agreement. Additionally, we have a limited history of prior indemnification claims and the payments we have made under such agreements have not had a material adverse effect on our results of operations, cash flows or financial position. However, to the extent that valid indemnification claims arise in the future, future payments by us could be significant and could have a material adverse effect on our results of operations or cash flows in a particular period. As of September 30, 2018 , we did not have any material indemnification claims that were probable or reasonably possible.

Stockholders' Equity (Notes)

Stockholders' Equity (Notes)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Stockholders' Equity	Stockholders’ Equity Summary of Stock-Based Compensation Expense As of September 30, 2018 , the 2005 Incentive Plan (as amended) has a total reserve of 27,783,379 shares of which 6,063,095 shares are available for issuance. Stock-based compensation is based on the estimated fair value of awards, net of estimated forfeitures, and recognized over the requisite service period. Estimated forfeitures are based on historical experience at the time of grant and may be revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The stock-based compensation related to all of our stock-based awards and employee stock purchases for the three and nine months ended September 30, 2018 and 2017 is as follows (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Cost of net revenues $ 966 $ 833 $ 2,747 $ 2,526 Selling, general and administrative 15,403 11,880 41,197 34,814 Research and development 2,829 2,254 7,974 6,684 Total stock-based compensation $ 19,198 $ 14,967 $ 51,918 $ 44,024 Stock Options We have not granted options since 2011 and all outstanding options were fully vested and associated stock-based compensation expenses was recognized as of December 31, 2015. Activity for the nine months ended September 30, 2018 under the stock option plans is set forth below: Number of Shares Underlying Stock Options (in thousands) Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2017 75 $ 11.36 Exercised (63 ) 11.99 Cancelled or expired — — Outstanding as of September 30, 2018 12 $ 7.99 0.41 $ 4,534 Vested at September 30, 2018 12 $ 7.99 0.41 $ 4,534 Exercisable at September 30, 2018 12 $ 7.99 0.41 $ 4,534 Restricted Stock Units (“RSUs”) The fair value of RSUs is based on our closing stock price on the date of grant. A summary for the nine months ended September 30, 2018 is as follows: Shares Underlying RSUs (in thousands) Weighted Average Grant Date Fair Value Weighted Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Nonvested as of December 31, 2017 1,341 $ 82.30 Granted 225 261.52 Vested and released (516 ) 73.44 Forfeited (74 ) 105.53 Nonvested as of September 30, 2018 976 $ 126.52 1.23 $ 381,710 As of September 30, 2018 , we expect to recognize $90.1 million of total unamortized compensation cost, net of estimated forfeitures, related to RSUs over a weighted average period of 2.1 years. Market-performance Based Restricted Stock Units (“MSUs”) We grant MSUs to our executive officers. Each MSU represents the right to one share of Align’s common stock. The actual number of MSUs which will be eligible to vest will be based on the performance of Align’s stock price relative to the performance of a stock market index over the vesting period, and certain MSU grants are also based on Align’s stock price at the end of the performance period. Generally, the vesting period of MSUs is three years. For MSUs granted during the nine months ended September 30, 2018 , the maximum number of MSUs which will be eligible to vest are between 250% to 300% of the MSUs initially granted. The following table summarizes the MSU performance for the nine months ended September 30, 2018 : Number of Shares Underlying MSUs (in thousands) Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Nonvested as of December 31, 2017 428 $ 78.53 Granted 208 266.78 Vested and released (312 ) 62.41 Forfeited — — Nonvested as of September 30, 2018 324 $ 215.07 1.41 $ 126,834 As of September 30, 2018 , we expect to recognize $44.6 million of total unamortized compensation cost, net of estimated forfeitures, related to MSUs over a weighted average period of 1.4 years. Employee Stock Purchase Plan (“ESPP”) In May 2010, our shareholders approved the 2010 Employee Stock Purchase Plan (the “2010 Purchase Plan”) which will continue until terminated by either the Board of Directors or its administrator. The maximum number of shares available for purchase under the 2010 Purchase Plan is 2,400,000 shares. As of September 30, 2018 , we have 571,778 shares available for future issuance. The fair value of the option component of the 2010 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Expected term (in years) 1.2 1.2 1.3 1.2 Expected volatility 35.7 % 28.8 % 35.2 % 26.8 % Risk-free interest rate 2.5 % 1.2 % 2.2 % 1.0 % Expected dividends — — — — Weighted average fair value at grant date $ 109.58 $ 47.02 $ 94.71 $ 31.36 As of September 30, 2018 , there was $3.3 million of total unamortized compensation costs related to employee stock purchases which we expect to be recognized over a weighted average period of 0.6 years.

Common Stock Repurchase Program

Common Stock Repurchase Programs	9 Months Ended
	Sep. 30, 2018
Disclosure Common Stock Repurchase Program Additional Information [Abstract]
Common Stock Repurchase Programs	Common Stock Repurchase Programs April 2014 Repurchase Program In January 2017, we repurchased on the open market approximately 0.04 million shares of our common stock at an average price of $96.37 per share, including commission for an aggregate purchase price of approximately $3.8 million , completing the April 2014 Repurchase Program. April 2016 Repurchase Program In April 2016, we announced that our Board of Directors had authorized a plan to repurchase up to $300.0 million of our common stock (“April 2016 Repurchase Program”). In May 2017, we entered into an accelerated share repurchase agreement ("2017 ASR") to repurchase $50.0 million of our common stock. The 2017 ASR was completed in August 2017. We received a total of approximately 0.4 million shares for an average share price of $146.48 . In November 2017, we repurchased on the open market approximately 0.2 million shares of our common stock at an average price of $243.40 per share, including commissions, for an aggregate purchase price of approximately $50.0 million . In February 2018, we repurchased on the open market approximately 0.4 million shares of our common stock at an average price of $252.24 per share, including commissions, for an aggregate purchase price of approximately $100.0 million . In July 2018, we repurchased on the open market approximately 0.3 million shares of our common stock at an average price of $350.08 per share, including commissions, for an aggregate purchase price of approximately $100.0 million , completing the April 2016 Repurchase Program. May 2018 Repurchase Program In May 2018, we announced that our Board of Directors had authorized a plan to repurchase up to $600.0 million of our common stock (“May 2018 Repurchase Program”). In August 2018, we repurchased on the open market approximately 0.1 million shares of our common stock at an average price of $356.54 per share, including commissions, for an aggregate purchase price of approximately $50.0 million . As of September 30, 2018, we have $550.0 million remaining under the May 2018 Repurchase Program.

Accounting for Income Taxes

Accounting for Income Taxes	9 Months Ended
	Sep. 30, 2018
Accounting for Income Taxes	Accounting for Income Taxes Our provision for income taxes was $ 24.6 million and $ 18.3 million for the three months ended September 30, 2018 and 2017 , respectively, representing effective tax rates of 19.4% and 17.9% , respectively. Our provision for income taxes was $35.2 million and $26.5 million for the nine months ended September 30, 2018 and 2017 , respectively, representing effective tax rates of 10.2% and 10.5% , respectively. As a result of the enactment of the TCJA, the U.S. federal statutory tax rate decreased from 35% to 21% effective January 1, 2018. Our effective tax rate differs from the statutory federal income tax rate of 21% and 35% for both the three and nine months ended September 30, 2018 and 2017 , respectively, mainly as a result of the recognition of excess tax benefits related to stock-based compensation, tax benefits recognized related to a statute of limitations expiration, and certain foreign earnings, primarily from the Netherlands and Costa Rica, being taxed at lower tax rates, partially offset by unfavorable tax impact of the TCJA, including non-deductible officers’ compensation described below. On August 21, 2018, the Internal Revenue Service (“IRS”) issued Notice 2018-68, which provides interpretative guidance on the application of the new executive compensation deduction limits enacted under the TCJA. Based upon our assessment of this new guidance, for the three and nine months ended September 30, 2018, we reversed $20.2 million of previously recognized tax benefits associated with officers’ stock-based compensation deductions. The increase in effective tax rate for the three months ended September 30, 2018 compared to the same period in 2017 is primarily attributable to the unfavorable tax impact from IRS Notice 2018-68 related to limitations on officers’ compensation deductions as described above and reduced tax benefits from foreign earnings being taxed at a lower tax rate due to the decrease in corporate tax rate from 35% to 21%, partially offset by the recognition of tax benefits related to a statute of limitations expiration. The decrease in effective tax rate for the nine months ended September 30, 2018 compared to the same period in 2017 is mainly driven by the decrease in corporate tax rate from 35% to 21% pursuant to the enactment of the TCJA, the recognition of tax benefits related to a statute of limitations expiration and the increase in excess tax benefits related to stock-based compensation, offset in part by the unfavorable tax impact of the TCJA including non-deductible officers’ compensation under IRS Notice 2018-68 described above and reduced tax benefits from foreign earnings being taxed at a lower rate. As a result of our assessment of the impact of IRS Notice 2018-68 mentioned above, we reversed $20.2 million of previously recognized tax benefits associated with officers’ stock-based compensation deductions which resulted in a tax expense accrual of $14.7 million for the three months ended September 30, 2018 . For the nine months ended September 30, 2018 , the excess tax benefits we recognized in our provision for income taxes related to stock-based compensation was $25.2 million . We exercise significant judgment in regards to estimates of future market growth, forecasted earnings and projected taxable income in determining the provision for income taxes and for purposes of assessing our ability to utilize any future benefit from deferred tax assets. We file U.S. federal, U.S. state, and non-U.S. income tax returns. Our major tax jurisdictions include U.S. federal, the State of California and the Netherlands. For U.S. federal and state tax returns, we are no longer subject to tax examinations for years before 2015 . We are currently under examination by the Internal Revenue Service for tax years 2015 and 2016. With few exceptions, we are no longer subject to examination by foreign tax authorities for years before 2010 . During the three and nine months ended September 30, 2018, a statute of limitations expired. As a result, we recorded approximately $29.0 million of previously unrecognized tax benefits and reduced our accrual for interest by approximately $2.9 million . Our total gross unrecognized tax benefits, excluding interest and penalties, was $27.1 million and $47.7 million as of September 30, 2018 and December 31, 2017 , respectively, all of which would impact our effective tax rate if recognized. Our total interest and penalties accrued as of September 30, 2018 was $0.8 million . We have elected to recognize interest and penalties related to unrecognized tax benefits as a component of income taxes. The timing and resolution of income tax examinations is uncertain, and the amounts ultimately paid, if any, upon resolution of issues raised by the taxing authorities may differ materially from the amounts accrued for each year. Although it is possible that our balance of gross unrecognized tax benefits could materially change in the next 12 months, given the uncertainty in the development of ongoing income tax examinations, we are unable to estimate the full range of possible adjustments to this balance. In June 2017, the Costa Rica Ministry of Foreign Trade, an agency of the Government of Costa Rica, granted an extension of certain income tax incentives for an additional twelve year period. Under these incentives, all of the income in Costa Rica is subject to a reduced tax rate. In order to receive the benefit of these incentives, we must hire specified numbers of employees and maintain certain minimum levels of fixed asset investment in Costa Rica. If we do not fulfill these conditions for any reason, our incentive could lapse and our income in Costa Rica would be subject to taxation at higher rates which could have a negative impact on our operating results. The Costa Rica corporate income tax rate that would apply, absent the incentives, is 30% for 2018 and 2017 . For the three and nine months ended September 30, 2018 , the reduction in income taxes due to the reduced tax rate was minimal. As of December 31, 2017 , our undistributed earnings totaled $606.5 million . We reassessed our capital needs and investment strategy with regard to the indefinite reinvestment of the undistributed earnings from certain of our foreign subsidiaries as a result of the one-time transition tax on cumulative foreign earnings under the TCJA. During the fourth quarter of 2017 , we determined that approximately $591.9 million of the total undistributed foreign earnings are no longer considered to be indefinitely reinvested outside the U.S. As a result, in the fourth quarter of 2017, we recorded a deferred tax liability of approximately $3.3 million , which represents the provisional amount of U.S. state income taxes that would be due in the event these foreign earnings are distributed. The remaining amount of undistributed foreign earnings of approximately $14.7 million continues to be indefinitely reinvested in our international operations. Since U.S. federal income tax has already been provided under the provisions of the TCJA, the additional tax impact of the distribution of such foreign earnings to the U.S. parent would be limited to U.S. state income and withholding taxes and is not significant. As of December 31, 2017 , we recorded a provisional tax charge for the estimated impact of the TCJA of $84.3 million , of which $73.9 million was related to a provisional transition tax liability on the mandatory deemed repatriation of foreign earnings and $10.4 million was related to the remeasurement of certain deferred tax assets and liabilities. During the nine months ended September 30, 2018 , the cumulative additional provisional tax charge recorded was $3.3 million , primarily resulting from further analysis of our cumulative foreign earnings balances affecting the U.S. transition tax liability and the corresponding state tax impact. As we complete our analysis of the TJCA, we may make further adjustments to the provisional amounts, which may impact our provision for income taxes in the period(s) in which the adjustments are made. The TCJA subjects a U.S. shareholder to tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740, No. 5, Accounting for Global Intangible Low-Taxed Income, states that an entity can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or provide for the tax expense related to GILTI in the year the tax is incurred as a period expense only. Given the complexity of the GILTI provisions, we are still evaluating the effects of the GILTI provisions and have not yet determined our accounting policy. As of September 30, 2018 , we are still evaluating the GILTI provisions and our analysis of future taxable income that is subject to GILTI. We have included GILTI related to current-year operations only in our estimated annual effective tax rate and have not provided additional GILTI on deferred items.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2018
Net Income Per Share	Net Income per Share Basic net income per share is computed using the weighted average number of shares of common stock outstanding during the period. Diluted net income per share is computed using the weighted average number of shares of common stock, adjusted for any dilutive effect of potential common stock. Potential common stock, computed using the treasury stock method, includes RSUs, MSUs, stock options and our ESPP. The following table sets forth the computation of basic and diluted net income per share attributable to common stock (in thousands, except per share amounts): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator: Net income $ 100,872 $ 82,555 $ 302,843 $ 221,154 Denominator: Weighted-average common shares outstanding, basic 80,111 80,163 80,122 80,086 Dilutive effect of potential common stock 1,248 1,626 1,416 1,671 Total shares, diluted 81,359 81,789 81,538 81,757 Net income per share, basic $ 1.26 $ 1.03 $ 3.78 $ 2.76 Net income per share, diluted $ 1.24 $ 1.01 $ 3.71 $ 2.71 For the three and nine months ended September 30, 2018 and 2017 , potentially anti-dilutive shares excluded from diluted net income per share related to RSUs, MSUs, stock options and ESPP were not material.

Segments and Geographical Infor

Segments and Geographical Information	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Segments and Geographical Information	Segments and Geographical Information Segment Information Operating segments are defined as components of an enterprise for which separate financial information is available that is evaluated regularly by the Chief Operating Decision Maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance. Our CODM is our Chief Executive Officer. We report segment information based on the management approach. The management approach designates the internal reporting used by CODM for decision making and performance assessment as the basis for determining our reportable segments. The performance measures of our reportable segments include net revenues, gross profit and income from operations. Income from operations for each segment includes all geographic revenues, related cost of net revenues and operating expenses directly attributable to the segment. Certain operating expenses are attributable to operating segments and each allocation is measured differently based on the specific facts and circumstances of the costs being allocated. Costs not specifically allocated to segment income from operations include various corporate expenses such as stock-based compensation and costs related to IT, facilities, human resources, accounting and finance, legal and regulatory, and other separately managed general and administrative costs outside the operating segments. We group our operations into two reportable segments: Clear Aligner segment and Scanner segment. • Our Clear Aligner segment consists of Comprehensive Products, Non-Comprehensive Products and Non-Case revenues as defined below: • Comprehensive Products include, but not limited to, Invisalign Comprehensive, Invisalign Full, Invisalign Teen, Invisalign Assist and Invisalign First. • Non-Comprehensive Products include, but not limited to, Invisalign Express, Invisalign Lite and Invisalign Go in addition to revenues from the sale of aligners to SDC under our supply agreement. • Non-Case includes, but not limited to, Vivera retainers along with our training and ancillary products for treating malocclusion. • Our Scanner segment consists of intraoral scanning systems and additional services available with the intraoral scanners that provide digital alternatives to the traditional cast models. This segment includes our iTero scanner and OrthoCAD services. These reportable operating segments are based on how our CODM views and evaluates our operations as well as allocation of resources. The following information relates to these segments (in thousands): Three Months Ended Nine Months Ended Net revenues 2018 2017 2018 2017 Clear Aligner $ 427,087 $ 341,611 $ 1,245,833 $ 945,046 Scanner 78,202 43,656 186,639 107,044 Total net revenues $ 505,289 $ 385,267 $ 1,432,472 $ 1,052,090 Gross profit Clear Aligner $ 321,772 $ 266,285 $ 950,360 $ 737,046 Scanner 50,009 26,203 114,411 61,984 Total gross profit $ 371,781 $ 292,488 $ 1,064,771 $ 799,030 Income from operations Clear Aligner $ 182,667 $ 154,614 $ 534,408 $ 403,264 Scanner 31,498 13,525 65,250 28,324 Unallocated corporate expenses (88,957 ) (69,376 ) (253,567 ) (187,583 ) Total income from operations $ 125,208 $ 98,763 $ 346,091 $ 244,005 Depreciation and amortization Clear Aligner $ 7,218 $ 5,643 $ 20,361 $ 15,607 Scanner 1,237 1,130 3,510 3,248 Unallocated corporate depreciation and amortization 5,664 3,199 14,314 7,860 Total depreciation and amortization $ 14,119 $ 9,972 $ 38,185 $ 26,715 The following table reconciles total segment income from operations in the table above to net income before provision for income taxes and equity losses of investee (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Total segment income from operations $ 214,165 $ 168,139 $ 599,658 $ 431,588 Unallocated corporate expenses (88,957 ) (69,376 ) (253,567 ) (187,583 ) Total income from operations 125,208 98,763 346,091 244,005 Interest income 2,234 1,826 6,327 4,462 Other income (expense), net (837 ) 1,924 (7,759 ) 4,145 Net income before provision for income taxes and equity in losses of investee $ 126,605 $ 102,513 $ 344,659 $ 252,612 Geographical Information Net revenues are presented below by geographic area (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net revenues 1 : United States $ 263,349 $ 217,758 $ 754,472 $ 608,052 The Netherlands 141,405 109,068 437,364 318,399 China 52,874 26,965 116,891 59,195 Other International 47,661 31,476 123,745 66,444 Total net revenues $ 505,289 $ 385,267 $ 1,432,472 $ 1,052,090 1 Net revenues are attributed to countries based on location of where revenues are recognized. Tangible long-lived assets are presented below by geographic area (in thousands): September 30, December 31, 2017 Long-lived assets 2 : The Netherlands $ 195,790 $ 143,673 United States 135,369 128,171 Costa Rica 71,437 30,738 Mexico 34,272 25,090 China 33,955 5,480 Other International 20,807 15,641 Total long-lived assets $ 491,630 $ 348,793 2 Long-lived assets are attributed to countries based on entity that owns the assets.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Basis of presentation	Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements have been prepared by Align Technology, Inc. (“we”, “our”, or “Align”) in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) and contains all adjustments, including normal recurring adjustments, necessary to state fairly our results of operations for the three and nine months ended September 30, 2018 and 2017 , our comprehensive income for the three and nine months ended September 30, 2018 and 2017 , our financial position as of September 30, 2018 and our cash flows for the nine months ended September 30, 2018 and 2017 . The Condensed Consolidated Balance Sheet as of December 31, 2017 was derived from the December 31, 2017 audited financial statements and have been recast to reflect the adoption of accounting standards as described below. It does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S.”). During the first quarter of fiscal year 2018, we adopted the Accounting Standards Codification (“ASC”) 606, “ Revenues from Contracts with Customers, ” using the full retrospective method and Accounting Standards Update (“ASU”) 2016-18, “ Statement of Cash Flows - Restricted Cash, ” on a retrospective basis. The Condensed Consolidated Balance Sheet as of December 31, 2017 and the Condensed Consolidated Statement of Cash Flow for the nine months ended September 30, 2017 have been recast to comply with the adoption of these standards. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or any other future period, and we make no representations related thereto. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Quantitative and Qualitative Disclosures About Market Risk” and the Consolidated Financial Statements and notes thereto included in Items 7, 7A and 8, respectively, in our Annual Report on Form 10-K for the year ended December 31, 2017 .
Use of estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles (“GAAP”) in the U.S. requires our management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. On an ongoing basis, we evaluate our estimates, including those related to the fair values of financial instruments, valuation of investments in privately held companies, useful lives of intangible assets and property and equipment, revenue recognition, stock-based compensation, long-lived assets and goodwill, income taxes and contingent liabilities, among others. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities.
Revenue Recognition	Revenue Recognition Our revenues are derived primarily from the sale of aligners, scanners, and services from our Clear Aligner and Scanner segments. We enter into sales contracts that may consist of multiple distinct performance obligations where certain performance obligations of the sales contract are not delivered in one reporting period. We measure and allocate revenues according to ASC 606-10, “ Revenues from Contracts with Customers. ” We identify a performance obligation as distinct if both of the following criteria are true: the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. Determining the standalone selling price (“SSP”) and allocation of consideration from a contract to the individual performance obligations, and the appropriate timing of revenue recognition, is the result of significant qualitative and quantitative judgments. Management considers a variety of factors such as historical sales, usage rates, costs, and expected margin, which may vary over time depending upon the unique facts and circumstances related to each performance obligation in making these estimates. While changes in the allocation of the SSP between performance obligations will not affect the amount of total revenues recognized for a particular contract, any material changes could impact the timing of revenue recognition, which would have a material effect on our financial position and result of operations. This is because the contract consideration is allocated to each performance obligation, delivered or undelivered, at the inception of the contract based on the SSP of each distinct performance obligation. Clear Aligner We enter into contracts (“treatment plan(s)”) that involve multiple future performance obligations. Invisalign Comprehensive, Invisalign Full, Invisalign Teen, Invisalign First, Invisalign Lite, Invisalign Express and Invisalign Assist products include optional additional aligners at no charge for a certain period of time, from one to five years after initial shipment, and Invisalign Go includes optional additional aligners at no charge for a period of up to two years after initial shipment. We determined that our treatment plans comprise the following performance obligations that also represent distinct deliverables: initial aligners, additional aligners, case refinement, and replacement aligners. We elected to take the practical expedient to consider shipping and handling costs as activities to fulfill the performance obligation. We allocate revenues for each treatment plan based on each unit’s SSP and recognize the revenues upon shipment, as the customers obtain physical possession and we have enforceable rights to payment. As we collect most consideration upfront, we considered whether a significant financing component exists; however, as the delivery of the performance obligations are at the customer’s discretion, we concluded that no significant financing component exists. Scanner We sell intraoral scanners and computer-aided design/computer-aided manufacturing (“CAD/CAM”) services through both our direct sales force and distribution partners. The intraoral scanner sales price includes one year of warranty and unlimited scanning services. The customer may also select, for additional fees, extended warranty and unlimited scanning services for periods beyond the initial year. When intraoral scanners are sold with an unlimited scanning service agreement and/or extended warranty, we allocate revenues based on each element’s SSP. We estimate the SSP of each element, taking into consideration historical prices as well as our discounting strategies. Revenues are then recognized over time as the monthly services are rendered and upon shipment for the scanner, as that is when we deem the customer to have obtained control. Most consideration is collected upfront and in cases where there are payment plans, consideration is collected by the one year mark and therefore, there are no significant financing components. Warranties For both Clear Aligner and Scanner segments, we offer an assurance warranty which provides the customer assurance that the product will function as the parties intended because it complies with agreed-upon specifications, and thus is not treated as a separate performance obligation and will continue to be accrued in accordance with the Financial Accounting Standards Board (“FASB”) guidance on guarantees. Volume Discounts In certain situations, we offer promotions in which the discount will increase depending upon the volume purchased over time. We concluded that in these situations, the promotions can represent either variable consideration or options, depending upon the specifics of the promotion. In the event the promotion contains an option, the option is considered a material right and, therefore, included in the accounting for the initial arrangement. We estimate the average anticipated discount over the lifetime of the promotion or contract, and apply that discount to each unit as it is sold. On a quarterly basis, we review our estimates and, if needed, updates are made and changes are applied prospectively. Costs to Obtain a Contract We offer a variety of commission plans to our salesforce; each plan has multiple components. To match the costs to obtain a contract to the associated revenue, we evaluate the individual components and capitalize the eligible components, recognizing the costs over the treatment period. Unfulfilled Performance Obligations for Clear Aligners and Scanners Our unfilled performance obligations as of September 30, 2018 and the estimated revenues expected to be recognized in the future related to these performance obligations are $380.7 million . This includes performance obligations from the Clear Aligner segment, primarily the shipment of additional aligners, which are fulfilled over one to five years, and performance obligations from the iTero scanner segment, primarily contracted deliveries of additional scanners and support, which are fulfilled over one to five years. The estimate includes both product and service unfulfilled performance obligations and the time range reflects our best estimate of when we will transfer control to the customer and may change based on customer usage patterns, timing of shipments, readiness of customers’ facilities for installation, and manufacturing availability. Contract Balances The timing of revenue recognition results in deferred revenues being recognized on the Condensed Consolidated Balance Sheet. For both aligners and scanners, we usually collect the total consideration owed prior to all performance obligations being performed and payment terms vary from net 30 to net 180 days. Contract liabilities are recorded as deferred revenue balances, which are generated based upon timing of invoices and recognition patterns, not payments. If the revenue recognition exceeds the billing, the exceeded amount is considered unbilled receivable and a contract asset. Conversely, if the billing occurs prior to the revenue recognition, the amount is considered deferred revenue and a contract liability.
Investments in Privately Held Companies	Investments in Privately Held Companies Investments in privately held companies in which we can exercise significant influence but do not own a majority equity interest or otherwise control are accounted for under ASC 323, “ Investments—Equity Method and Joint Ventures. ” Equity securities qualified as equity method investments are reported on our Condensed Consolidated Balance Sheet as a single amount, and we record our share of their operating results within equity in losses of investee, net of tax, in our Condensed Consolidated Statement of Operations. Investments in privately held companies in which we cannot exercise significant influence and do not own a majority equity interest or otherwise control are accounted for under ASC 321, “ Investments—Equity Securities. ” The equity securities without readily determinable fair values are recorded at cost and adjusted for impairments and observable price changes with a same or similar security from the same issuer (“Measurement Alternative”). Equity securities under ASC 321 are reported on our Condensed Consolidated Balance Sheet as other assets, and we record a change in carrying value of our equity securities, if any, in other income (expense), net in our Condensed Consolidated Statement of Operations. Equity securities are evaluated for impairment as events or circumstances indicate that there is an other-than-temporary loss in value. The decrease in value is recognized in the period the impairment occurs and recorded in other income (expense), net in the Condensed Consolidated Statement of Operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements (i) New Accounting Updates Recently Adopted In May 2014, the FASB released ASU 2014-09, “ Revenue from Contracts with Customers, ” (Topic 606) to supersede nearly all existing revenue recognition guidance under GAAP. The core principle of the standard is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for the goods or services. We adopted the guidance in the first quarter of fiscal year 2018 by applying the full retrospective method. The impact of adoption was primarily related to the Clear Aligner segment. Our disaggregation of revenues can be found in Note 14 “Segments and Geographical Information.” We elected to take the practical expedient to exclude from the transaction price all taxes assessed by a governmental authority. In preparation for adoption of the standard, we have reviewed and, where necessary, implemented additional key system functionalities and internal controls to enable the preparation of financial information. Prior periods have been retrospectively adjusted, and we recognized cumulative effect of adopting the guidance as an adjustment to our opening balance of retained earnings as of January 1, 2016. The adoption of ASU 2014-09 did not have a material impact on our Condensed Consolidated Statements of Operations, Condensed Consolidated Statements of Comprehensive Income or Condensed Consolidated Statements of Cash Flows for the historical periods presented in the Item 1 Financial Statements section. Consolidated Balance Sheet line items, which reflect the adoption of the ASU 2014-09 are as follows (in thousands): December 31, 2017 As Previously Reported Adjustment As Adjusted Asset Accounts: Accounts receivable, net $ 322,825 $ 1,364 $ 324,189 Deferred tax assets 50,059 (725 ) 49,334 Other assets 38,379 5,514 43,893 Liability and Stockholders’ Equity Accounts: Accrued liabilities $ 194,198 $ 1,364 $ 195,562 Deferred revenues 266,842 871 267,713 Retained earnings 263,356 3,918 267,274 In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments,” which clarifies the presentation and classification of certain cash receipts and cash payments in the statements of cash flows. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017. We adopted the standard in the first quarter of fiscal year 2018 on a retrospective basis, and it did not have an impact on our Condensed Consolidated Statements of Cash Flows. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows—Restricted Cash,” which provides guidance to address the classification and presentation of changes in restricted cash in the statements of cash flows . The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 on a retrospective basis. We adopted the guidance in the first quarter of fiscal year 2018 on a retrospective basis and presented the changes in the total of cash, cash equivalents, and restricted cash in the Condensed Consolidated Statements of Cash Flows. Condensed Consolidated Statement of Cash Flows line items, which reflect the adoption of the ASU 2016-18, are as follows (in thousands): Nine Months Ended September 30, 2017 As Previously Reported Adjustment As Adjusted Cash Flows from Investing Activities Other investing activities $ 397 $ (3,164 ) $ (2,767 ) Net cash used in investing activities (228,620 ) (3,164 ) (231,784 ) Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash 4,781 25 4,806 Net decrease in cash, cash equivalents, and restricted cash (26,662 ) (3,139 ) (29,801 ) Cash, cash equivalents, and restricted cash at beginning of the period 389,275 3,744 393,019 Cash, cash equivalents, and restricted cash at end of the period $ 362,613 $ 605 $ 363,218 In May 2017, the FASB issued ASU 2017-09, “ Compensation — Stock Compensation (Topic 718): Scope of Modification Accounting,” to clarify when to account for a change to the terms or conditions of a share-based payment award as a modification. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 on a prospective basis. We adopted the standard in the first quarter of fiscal year 2018 on a prospective basis which did not have an impact on our condensed consolidated financial statements and related disclosures. (ii) Recent Accounting Updates Not Yet Effective In February 2016, the FASB issued ASU 2016-02, “ Leases ” (Topic 842) to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The updated guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. In July 2018, the FASB issued ASU 2018-11, “ Leases- Targeted Improvements, ” which p rovides an additional transition method by allowing entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings. We plan to adopt the standard in the first quarter of fiscal year 2019 by electing the transition method issued in ASU 2018-11 and the package of practical expedients available in the standard. In addition, we are in the process of implementing changes to our systems, processes and controls and are currently evaluating the impact of the adoption of this guidance on our consolidated financial statements. We expect the adoption will have a material increase in assets and liabilities on our consolidated balance sheet. In June 2016, the FASB issued ASU 2016-13, “ Financial Instruments - Credit Losses ” (Topic 326) . The FASB issued this update to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments in this update replace the existing guidance of incurred loss impairment methodology with an approach that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The updated guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption of the update is permitted in fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU 2017-04, “Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” to simplify the subsequent measurement of goodwill by eliminating step two from the goodwill impairment test. Under the amendments, an entity will recognize an impairment charge for the amount by which the carrying value exceeds the fair value. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 on a prospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In February 2018, the FASB issued ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” which gives entities the option to reclassify to retained earnings the tax effects resulting from the U.S. Tax Cuts and Jobs Act (the “TCJA”) related to items in accumulated other comprehensive income. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2018 on a retrospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-13, “ Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement,” to modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement . The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 on a prospective basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our related disclosures. In August 2018, the FASB issued ASU 2018-15, “ Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” to clarify the guidance on the costs of implementing a cloud computing hosting arrangement that is a service contract. Under the amendments, the entity is required to follow the guidance in Subtopic 350-40, Internal-Use Software , to determine which implementation costs under the service contract to be capitalized as an asset and which costs to expense. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2019 either on a retrospective or prospectively basis and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	Consolidated Balance Sheet line items, which reflect the adoption of the ASU 2014-09 are as follows (in thousands): December 31, 2017 As Previously Reported Adjustment As Adjusted Asset Accounts: Accounts receivable, net $ 322,825 $ 1,364 $ 324,189 Deferred tax assets 50,059 (725 ) 49,334 Other assets 38,379 5,514 43,893 Liability and Stockholders’ Equity Accounts: Accrued liabilities $ 194,198 $ 1,364 $ 195,562 Deferred revenues 266,842 871 267,713 Retained earnings 263,356 3,918 267,274 Condensed Consolidated Statement of Cash Flows line items, which reflect the adoption of the ASU 2016-18, are as follows (in thousands): Nine Months Ended September 30, 2017 As Previously Reported Adjustment As Adjusted Cash Flows from Investing Activities Other investing activities $ 397 $ (3,164 ) $ (2,767 ) Net cash used in investing activities (228,620 ) (3,164 ) (231,784 ) Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash 4,781 25 4,806 Net decrease in cash, cash equivalents, and restricted cash (26,662 ) (3,139 ) (29,801 ) Cash, cash equivalents, and restricted cash at beginning of the period 389,275 3,744 393,019 Cash, cash equivalents, and restricted cash at end of the period $ 362,613 $ 605 $ 363,218

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Short-Term And Long-Term Marketable Securities	As of September 30, 2018 and December 31, 2017 , the estimated fair value of our short-term and long-term marketable securities, classified as available for sale, are as follows (in thousands): Short-term September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 24,675 $ — $ — $ 24,675 Corporate bonds 75,461 1 (94 ) 75,368 U.S. government agency bonds 11,665 — (31 ) 11,634 U.S. government treasury bonds 72,622 — (22 ) 72,600 Certificates of deposit 20 — — 20 Total marketable securities, short-term $ 184,443 $ 1 $ (147 ) $ 184,297 Long-term September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. government agency bonds $ 7,035 $ — $ (74 ) $ 6,961 Corporate bonds 1,127 3 — 1,130 Total marketable securities, long-term $ 8,162 $ 3 $ (74 ) $ 8,091 Short-term December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 58,503 $ — $ (1 ) $ 58,502 Corporate bonds 145,728 3 (174 ) 145,557 U.S. government agency bonds 3,013 — (7 ) 3,006 U.S. government treasury bonds 60,650 — (70 ) 60,580 Certificates of deposit 4,386 — — 4,386 Total marketable securities, short-term $ 272,280 $ 3 $ (252 ) $ 272,031 Long-term December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. government agency bonds $ 15,023 $ — $ (68 ) $ 14,955 Corporate bonds 25,067 2 (76 ) 24,993 Total marketable securities, long-term $ 40,090 $ 2 $ (144 ) $ 39,948
Investments Classified by Contractual Maturity Date	As the carrying value approximates the fair value for our short-term and long-term marketable securities shown in the tables above, the following table summarizes the fair value of our short-term and long-term marketable securities classified by contractual maturity as of September 30, 2018 and December 31, 2017 (in thousands): September 30, December 31, One year or less $ 184,297 $ 272,031 Due in greater than one year 8,091 39,948 Total available for sale short-term and long-term marketable securities $ 192,388 $ 311,979
Investments in privately held companies	Our investments in privately held companies as of September 30, 2018 and December 31, 2017 are as follows (in thousands): September 30, December 31, Equity securities under the equity method investment 1 $ 47,996 $ 54,606 Equity securities without readily determinable fair values 2 $ 9,862 $ — 1 Refer to Note 4 “Equity Method Investments” of the Notes to Condensed Consolidated Financial Statements for more information 2 In April 2018, $4.9 million of convertible short term notes receivable (recurring Level 3 investment) was converted into equity securities as a result of qualified financing secured by the private company in accordance with ASC 321, “Investments—Equity Securities.” The equity securities issued upon conversion are reported as a nonrecurring investment within other assets in our Condensed Consolidated Balance Sheet. During the three and nine months ended September 30, 2018 , there were no fair value adjustments to equity securities without readily determinable fair values.
Financial Assets Measured At Fair Value On Recurring Basis	The following tables summarize our financial assets measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017 (in thousands): Description Balance as of September 30, 2018 Level 1 Level 2 Cash equivalents: Money market funds $ 256,689 $ 256,689 $ — Commercial paper 6,883 — 6,883 Corporate bonds 2,014 — 2,014 Short-term investments: Commercial paper 24,675 — 24,675 Corporate bonds 75,368 — 75,368 U.S. government agency bonds 11,634 — 11,634 U.S. government treasury bonds 72,600 72,600 — Certificates of deposit 20 — 20 Long-term investments: U.S. government agency bonds 6,961 — 6,961 Corporate bonds 1,130 — 1,130 Prepaid expenses and other current assets: Israeli funds 3,143 — 3,143 $ 461,117 $ 329,289 $ 131,828 Description Balance as of December 31, 2017 Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 253,155 $ 253,155 $ — $ — Commercial paper 7,246 — 7,246 — Corporate bonds 2,016 — 2,016 — Short-term investments: Commercial paper 58,502 — 58,502 — Corporate bonds 145,557 — 145,557 — U.S. government agency bonds 3,006 — 3,006 — U.S. government treasury bonds 60,580 60,580 — — Certificates of deposit 4,386 — 4,386 — Long-term investments: U.S. government agency bonds 14,955 — 14,955 — Corporate bonds 24,993 — 24,993 — Prepaid expenses and other current assets: Israeli funds 3,075 — 3,075 — Short-term notes receivable 4,476 — — 4,476 $ 581,947 $ 313,735 $ 263,736 $ 4,476
Notional value of derivative instruments	The following table presents the gross notional value of all our foreign exchange forward contracts outstanding as of September 30, 2018 (in thousands): September 30, 2018 Local Currency Amount Notional Contract Amount (USD) Euro €61,000 $ 70,992 Chinese Yuan ¥330,000 47,882 Canadian Dollar C$28,000 21,653 British Pound £13,000 16,966 Japanese Yen ¥1,700,000 14,985 Brazilian Real R$55,500 13,821 Australian Dollar A$2,900 2,097 $ 188,396

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): September 30, December 31, Raw materials $ 23,395 $ 12,721 Work in process 11,090 12,157 Finished goods 14,373 6,810 Total inventories $ 48,858 $ 31,688
Schedule of Other Assets	Other assets consist of the following (in thousands): September 30, December 31, Capitalized commissions $ 8,651 $ 5,515 Equity securities 9,862 — Security deposits 4,259 3,557 Loan receivable from equity investee — 30,000 Other long-term assets 2,692 4,821 Total other assets $ 25,464 $ 43,893
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands): September 30, December 31, Accrued payroll and benefits $ 102,109 $ 103,004 Accrued expenses 36,110 27,318 Accrued fixed assets 17,765 11,362 Accrued warranty 8,026 5,929 Accrued professional fees 7,774 6,316 Accrued sales rebate 7,765 11,209 Accrued customer credits 7,618 5,373 Accrued sales tax and value added tax 6,734 5,503 Accrued sales return reserve 1 5,876 1,364 Accrued income taxes 4,111 12,405 Other accrued liabilities 15,147 5,779 Total accrued liabilities $ 219,035 $ 195,562 1 December 31, 2017 balance has been reclassified from accounts receivable, net to reflect the adoption of ASU 2014-09 ( Refer to Note 1 “Summary of Significant Accounting Policies” of the Notes to Condensed Consolidated Financial Statements for more information).
Schedule of Warranty Accrual	Warranty accrual as of September 30, 2018 and 2017 consists of the following activity (in thousands): Nine Months Ended 2018 2017 Balance at beginning of period $ 5,929 $ 3,841 Charged to cost of revenues 10,874 5,201 Actual warranty expenditures (8,777 ) (3,987 ) Balance at end of period $ 8,026 $ 5,055
Schedule of Deferred Revenues	Deferred revenues consist of the following (in thousands): September 30, December 31, Deferred revenues - current $ 356,109 $ 267,713 Deferred revenues - long-term 1 11,739 4,588 1 Included in other long-term liabilities within our Condensed Consolidated Balance Sheets

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Summary of Goodwill by Reportable Segment	The change in the carrying value of goodwill for the nine months ended September 30, 2018 , all attributable to our Clear Aligner reporting unit, is as follows (in thousands): Total Balance as of December 31, 2017 $ 64,614 Adjustments 1 (542 ) Balance as of September 30, 2018 $ 64,072 1 The adjustments to goodwill during the period were a result of foreign currency translation
Schedule of Amortized Intangible Assets	Acquired intangible long-lived assets are being amortized as follows (in thousands): Weighted Average Amortization Period (in years) Gross Carrying Amount as of Accumulated Amortization Accumulated Impairment Loss Net Carrying Trademarks 15 $ 7,100 $ (1,873 ) $ (4,179 ) $ 1,048 Existing technology 13 12,600 (5,127 ) (4,328 ) 3,145 Customer relationships 11 33,500 (16,078 ) (10,751 ) 6,671 Reacquired rights 3 7,500 (3,604 ) — 3,896 Patents 8 6,796 (2,126 ) — 4,670 Other 2 618 (513 ) — 105 Total intangible assets $ 68,114 $ (29,321 ) $ (19,258 ) $ 19,535 Weighted Average Amortization Period (in years) Gross Carrying Amount as of December 31, 2017 Accumulated Amortization Accumulated Impairment Loss Net Carrying Value as of December 31, 2017 Trademarks 15 $ 7,100 $ (1,769 ) $ (4,179 ) $ 1,152 Existing technology 13 12,600 (4,704 ) (4,328 ) 3,568 Customer relationships 11 33,500 (14,681 ) (10,751 ) 8,068 Reacquired rights 3 7,500 (1,356 ) — 6,144 Patents 8 6,798 (1,504 ) — 5,294 Other 2 618 (390 ) — 228 Total intangible assets $ 68,116 $ (24,404 ) $ (19,258 ) $ 24,454
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The total estimated annual future amortization expense for these acquired intangible assets as of September 30, 2018 is as follows (in thousands): Fiscal Year Ending December 31, Amortization Remainder of 2018 $ 1,571 2019 6,171 2020 3,854 2021 3,388 2022 2,116 Thereafter 2,435 Total $ 19,535

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Schedule of Future Lease Payments	As of September 30, 2018 , minimum future lease payments for non-cancelable operating leases are as follows (in thousands): Fiscal Year Ending December 31, Operating Leases Remainder of 2018 $ 4,839 2019 19,131 2020 15,988 2021 14,386 2022 12,026 Thereafter 25,769 Total minimum future lease payments $ 92,139

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Stock-based Compensation Expense	The stock-based compensation related to all of our stock-based awards and employee stock purchases for the three and nine months ended September 30, 2018 and 2017 is as follows (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Cost of net revenues $ 966 $ 833 $ 2,747 $ 2,526 Selling, general and administrative 15,403 11,880 41,197 34,814 Research and development 2,829 2,254 7,974 6,684 Total stock-based compensation $ 19,198 $ 14,967 $ 51,918 $ 44,024
Stock Option Activity	Activity for the nine months ended September 30, 2018 under the stock option plans is set forth below: Number of Shares Underlying Stock Options (in thousands) Weighted Average Exercise Price per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2017 75 $ 11.36 Exercised (63 ) 11.99 Cancelled or expired — — Outstanding as of September 30, 2018 12 $ 7.99 0.41 $ 4,534 Vested at September 30, 2018 12 $ 7.99 0.41 $ 4,534 Exercisable at September 30, 2018 12 $ 7.99 0.41 $ 4,534
Summary Of Restricted Stock Units	A summary for the nine months ended September 30, 2018 is as follows: Shares Underlying RSUs (in thousands) Weighted Average Grant Date Fair Value Weighted Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Nonvested as of December 31, 2017 1,341 $ 82.30 Granted 225 261.52 Vested and released (516 ) 73.44 Forfeited (74 ) 105.53 Nonvested as of September 30, 2018 976 $ 126.52 1.23 $ 381,710
Summary Of Market-performance Based Restricted Stock Units	The following table summarizes the MSU performance for the nine months ended September 30, 2018 : Number of Shares Underlying MSUs (in thousands) Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Nonvested as of December 31, 2017 428 $ 78.53 Granted 208 266.78 Vested and released (312 ) 62.41 Forfeited — — Nonvested as of September 30, 2018 324 $ 215.07 1.41 $ 126,834
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions	The fair value of the option component of the 2010 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Expected term (in years) 1.2 1.2 1.3 1.2 Expected volatility 35.7 % 28.8 % 35.2 % 26.8 % Risk-free interest rate 2.5 % 1.2 % 2.2 % 1.0 % Expected dividends — — — — Weighted average fair value at grant date $ 109.58 $ 47.02 $ 94.71 $ 31.36

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule Of Earnings Per Share Basic And Diluted	The following table sets forth the computation of basic and diluted net income per share attributable to common stock (in thousands, except per share amounts): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Numerator: Net income $ 100,872 $ 82,555 $ 302,843 $ 221,154 Denominator: Weighted-average common shares outstanding, basic 80,111 80,163 80,122 80,086 Dilutive effect of potential common stock 1,248 1,626 1,416 1,671 Total shares, diluted 81,359 81,789 81,538 81,757 Net income per share, basic $ 1.26 $ 1.03 $ 3.78 $ 2.76 Net income per share, diluted $ 1.24 $ 1.01 $ 3.71 $ 2.71

Segments and Geographical Inf_2

Segments and Geographical Information (Tables)	9 Months Ended
	Sep. 30, 2018
Notes To Financial Statements [Abstract]
Schedule of Segment Reporting Information, by Segment	These reportable operating segments are based on how our CODM views and evaluates our operations as well as allocation of resources. The following information relates to these segments (in thousands): Three Months Ended Nine Months Ended Net revenues 2018 2017 2018 2017 Clear Aligner $ 427,087 $ 341,611 $ 1,245,833 $ 945,046 Scanner 78,202 43,656 186,639 107,044 Total net revenues $ 505,289 $ 385,267 $ 1,432,472 $ 1,052,090 Gross profit Clear Aligner $ 321,772 $ 266,285 $ 950,360 $ 737,046 Scanner 50,009 26,203 114,411 61,984 Total gross profit $ 371,781 $ 292,488 $ 1,064,771 $ 799,030 Income from operations Clear Aligner $ 182,667 $ 154,614 $ 534,408 $ 403,264 Scanner 31,498 13,525 65,250 28,324 Unallocated corporate expenses (88,957 ) (69,376 ) (253,567 ) (187,583 ) Total income from operations $ 125,208 $ 98,763 $ 346,091 $ 244,005 Depreciation and amortization Clear Aligner $ 7,218 $ 5,643 $ 20,361 $ 15,607 Scanner 1,237 1,130 3,510 3,248 Unallocated corporate depreciation and amortization 5,664 3,199 14,314 7,860 Total depreciation and amortization $ 14,119 $ 9,972 $ 38,185 $ 26,715 The following table reconciles total segment income from operations in the table above to net income before provision for income taxes and equity losses of investee (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Total segment income from operations $ 214,165 $ 168,139 $ 599,658 $ 431,588 Unallocated corporate expenses (88,957 ) (69,376 ) (253,567 ) (187,583 ) Total income from operations 125,208 98,763 346,091 244,005 Interest income 2,234 1,826 6,327 4,462 Other income (expense), net (837 ) 1,924 (7,759 ) 4,145 Net income before provision for income taxes and equity in losses of investee $ 126,605 $ 102,513 $ 344,659 $ 252,612
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	Net revenues are presented below by geographic area (in thousands): Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net revenues 1 : United States $ 263,349 $ 217,758 $ 754,472 $ 608,052 The Netherlands 141,405 109,068 437,364 318,399 China 52,874 26,965 116,891 59,195 Other International 47,661 31,476 123,745 66,444 Total net revenues $ 505,289 $ 385,267 $ 1,432,472 $ 1,052,090 1 Net revenues are attributed to countries based on location of where revenues are recognized. Tangible long-lived assets are presented below by geographic area (in thousands): September 30, December 31, 2017 Long-lived assets 2 : The Netherlands $ 195,790 $ 143,673 United States 135,369 128,171 Costa Rica 71,437 30,738 Mexico 34,272 25,090 China 33,955 5,480 Other International 20,807 15,641 Total long-lived assets $ 491,630 $ 348,793 2 Long-lived assets are attributed to countries based on entity that owns the assets.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Notes To Financial Statements [Abstract]
Revenue remaining performance obligation	$ 380.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	5 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Balance sheet as adjusted (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 420,276	$ 324,189
Deferred tax assets	47,435	49,334
Other assets	25,464	43,893
Accrued liabilities	219,035	195,562
Deferred revenues	356,109	267,713
Retained earnings	$ 328,432	267,274
As Previously Reported | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net		322,825
Deferred tax assets		50,059
Other assets		38,379
Accrued liabilities		194,198
Deferred revenues		266,842
Retained earnings		263,356
Adjustment | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net		1,364
Deferred tax assets		(725)
Other assets		5,514
Accrued liabilities		1,364
Deferred revenues		871
Retained earnings		$ 3,918

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Cash flow statement as adjusted (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Initial Application Period [Line Items]
Other investing activities	$ 604	$ (2,767)
Net cash used in investing activities	(24,021)	(231,784)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	(2,890)	4,806
Net decrease in cash, cash equivalents, and restricted cash		(29,801)
Cash, cash equivalents, and restricted cash at beginning of the period	450,125	393,019
Cash, cash equivalents, and restricted cash at end of the period	$ 421,449	363,218
As Previously Reported
Initial Application Period [Line Items]
Other investing activities		397
Net cash used in investing activities		(228,620)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash		4,781
Net decrease in cash, cash equivalents, and restricted cash		(26,662)
Cash, cash equivalents, and restricted cash at beginning of the period		389,275
Cash, cash equivalents, and restricted cash at end of the period		362,613
Accounting Standards Update 2016-18 | Adjustment
Initial Application Period [Line Items]
Other investing activities		(3,164)
Net cash used in investing activities		(3,164)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash		25
Net decrease in cash, cash equivalents, and restricted cash		(3,139)
Cash, cash equivalents, and restricted cash at beginning of the period		3,744
Cash, cash equivalents, and restricted cash at end of the period		$ 605

Investments and Fair Value Me_3

Investments and Fair Value Measurements Short-Term and Long-Term Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Total available for sale short-term and long-term marketable securities	$ 192,388	$ 311,979
Fair Value, Measurements, Recurring | Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	184,443	272,280
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(147)	(252)
Total available for sale short-term and long-term marketable securities	184,297	272,031
Fair Value, Measurements, Recurring | Short-term Investments | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,675	58,503
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Total available for sale short-term and long-term marketable securities	24,675	58,502
Fair Value, Measurements, Recurring | Short-term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	75,461	145,728
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(94)	(174)
Total available for sale short-term and long-term marketable securities	75,368	145,557
Fair Value, Measurements, Recurring | Short-term Investments | U.S. government agency bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,665	3,013
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(31)	(7)
Total available for sale short-term and long-term marketable securities	11,634	3,006
Fair Value, Measurements, Recurring | Short-term Investments | U.S. government treasury bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	72,622	60,650
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(22)	(70)
Total available for sale short-term and long-term marketable securities	72,600	60,580
Fair Value, Measurements, Recurring | Short-term Investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20	4,386
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total available for sale short-term and long-term marketable securities	20	4,386
Fair Value, Measurements, Recurring | Long-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,162	40,090
Gross Unrealized Gains	3	2
Gross Unrealized Losses	(74)	(144)
Total available for sale short-term and long-term marketable securities	8,091	39,948
Fair Value, Measurements, Recurring | Long-term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,127	25,067
Gross Unrealized Gains	3	2
Gross Unrealized Losses	0	(76)
Total available for sale short-term and long-term marketable securities	1,130	24,993
Fair Value, Measurements, Recurring | Long-term Investments | U.S. government agency bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,035	15,023
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(74)	(68)
Total available for sale short-term and long-term marketable securities	$ 6,961	$ 14,955

Investments and Fair Value Me_4

Investments and Fair Value Measurements Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Original maturity of highly liquid investments included in cash and cash equivalents	40 months
Weighted average maturity	3 months	6 months

Investments and Fair Value Me_5

Investments and Fair Value Measurements Available For Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
One year or less	$ 184,297	$ 272,031
Due in greater than one year	8,091	39,948
Total available for sale short-term and long-term marketable securities	$ 192,388	$ 311,979

Investments and Fair Value Me_6

Investments and Fair Value Measurements Investments in Privately Held Companies (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Equity securities under the equity method investment	$ 47,996		$ 54,606
Equity securities without readily determinable fair values	$ 9,862		0
Fair Value, Measurements, Recurring | Short-term notes receivable
Schedule of Available-for-sale Securities [Line Items]
Short-term notes receivable			4,476
Level 3 | Fair Value, Measurements, Recurring | Short-term notes receivable
Schedule of Available-for-sale Securities [Line Items]
Short-term notes receivable		$ 4,900	$ 4,476

Investments and Fair Value Me_7

Investments and Fair Value Measurements Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$ 192,388		$ 311,979
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, Fair Value Disclosure	461,117		581,947
Fair Value, Measurements, Recurring | Prepaid expenses and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	3,143		3,075
Fair Value, Measurements, Recurring | Short-term notes receivable
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term notes receivable			4,476
Fair Value, Measurements, Recurring | Cash Equivalents | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	256,689		253,155
Fair Value, Measurements, Recurring | Cash Equivalents | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	6,883		7,246
Fair Value, Measurements, Recurring | Cash Equivalents | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	2,014		2,016
Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	184,297		272,031
Fair Value, Measurements, Recurring | Short-term Investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	24,675		58,502
Fair Value, Measurements, Recurring | Short-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	75,368		145,557
Fair Value, Measurements, Recurring | Short-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,634		3,006
Fair Value, Measurements, Recurring | Short-term Investments | U.S. government treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	72,600		60,580
Fair Value, Measurements, Recurring | Short-term Investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20		4,386
Fair Value, Measurements, Recurring | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	8,091		39,948
Fair Value, Measurements, Recurring | Long-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,130		24,993
Fair Value, Measurements, Recurring | Long-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	6,961		14,955
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, Fair Value Disclosure	329,289		313,735
Fair Value, Measurements, Recurring | Level 1 | Prepaid expenses and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	0		0
Fair Value, Measurements, Recurring | Level 1 | Short-term notes receivable
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term notes receivable			0
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	256,689		253,155
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0		0
Fair Value, Measurements, Recurring | Level 1 | Cash Equivalents | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0		0
Fair Value, Measurements, Recurring | Level 1 | Short-term Investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 1 | Short-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 1 | Short-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 1 | Short-term Investments | U.S. government treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	72,600		60,580
Fair Value, Measurements, Recurring | Level 1 | Short-term Investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 1 | Long-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 1 | Long-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, Fair Value Disclosure	131,828		263,736
Fair Value, Measurements, Recurring | Level 2 | Prepaid expenses and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	3,143		3,075
Fair Value, Measurements, Recurring | Level 2 | Short-term notes receivable
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term notes receivable			0
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0		0
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	6,883		7,246
Fair Value, Measurements, Recurring | Level 2 | Cash Equivalents | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	2,014		2,016
Fair Value, Measurements, Recurring | Level 2 | Short-term Investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	24,675		58,502
Fair Value, Measurements, Recurring | Level 2 | Short-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	75,368		145,557
Fair Value, Measurements, Recurring | Level 2 | Short-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,634		3,006
Fair Value, Measurements, Recurring | Level 2 | Short-term Investments | U.S. government treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0		0
Fair Value, Measurements, Recurring | Level 2 | Short-term Investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20		4,386
Fair Value, Measurements, Recurring | Level 2 | Long-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,130		24,993
Fair Value, Measurements, Recurring | Level 2 | Long-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$ 6,961		14,955
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets, Fair Value Disclosure			4,476
Fair Value, Measurements, Recurring | Level 3 | Prepaid expenses and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets			0
Fair Value, Measurements, Recurring | Level 3 | Short-term notes receivable
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term notes receivable		$ 4,900	4,476
Fair Value, Measurements, Recurring | Level 3 | Cash Equivalents | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents			0
Fair Value, Measurements, Recurring | Level 3 | Cash Equivalents | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents			0
Fair Value, Measurements, Recurring | Level 3 | Cash Equivalents | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents			0
Fair Value, Measurements, Recurring | Level 3 | Short-term Investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Short-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Short-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Short-term Investments | U.S. government treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Short-term Investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Long-term Investments | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			0
Fair Value, Measurements, Recurring | Level 3 | Long-term Investments | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments			$ 0

Investments and Fair Value Me_8

Investments and Fair Value Measurements Derivative Notional Instruments (Details) - Foreign Exchange Forward € in Thousands, ¥ in Thousands, ¥ in Thousands, £ in Thousands, R$ in Thousands, $ in Thousands, $ in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018EUR (€)	Sep. 30, 2018CNY (¥)	Sep. 30, 2018USD ($)	Sep. 30, 2018JPY (¥)	Sep. 30, 2018AUD ($)	Sep. 30, 2018BRL (R$)	Sep. 30, 2018CAD ($)	Sep. 30, 2018GBP (£)
Derivative [Line Items]
Gain on foreign currency forward contracts	$ 2,300	$ 7,700
Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					$ 188,396
Euro | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount			€ 61,000		70,992
Chinese Yuan | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount				¥ 330,000	47,882
Canadian Dollar | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					21,653				$ 28,000
British Pound | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					16,966					£ 13,000
Japanese Yen | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					14,985	¥ 1,700,000
Brazilian Real | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					13,821			R$ 55500
Australian Dollar | Level 2 | Prepaid expenses and other current assets
Derivative [Line Items]
Notional amount					$ 2,097		$ 2,900

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Disclosure Inventories [Abstract]
Raw materials	$ 23,395	$ 12,721
Work in process	11,090	12,157
Finished goods	14,373	6,810
Total inventories	$ 48,858	$ 31,688

Balance Sheet Components Other

Balance Sheet Components Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Notes To Financial Statements [Abstract]
Capitalized commissions	$ 8,651	$ 5,515
Equity securities	9,862	0
Security deposits	4,259	3,557
Loan receivable from equity investee	0	30,000
Other long-term assets	2,692	4,821
Total other assets	$ 25,464	$ 43,893

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Disclosure Accrued Liabilities [Abstract]
Accrued payroll and benefits	$ 102,109	$ 103,004
Accrued expenses	36,110	27,318
Accrued fixed assets	17,765	11,362
Accrued warranty	8,026	5,929
Accrued professional fees	7,774	6,316
Accrued sales rebate	7,765	11,209
Accrued customer credits	7,618	5,373
Accrued sales tax and value added tax	6,734	5,503
Accrued sales return reserve	5,876	1,364
Accrued income taxes	4,111	12,405
Other accrued liabilities	15,147	5,779
Total accrued liabilities	$ 219,035	$ 195,562

Warranty Accrual Activity (Deta

Warranty Accrual Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 5,929	$ 3,841
Charged to cost of revenues	10,874	5,201
Actual warranty expenditures	(8,777)	(3,987)
Balance at end of period	$ 8,026	$ 5,055

Balance Sheet Components Deferr

Balance Sheet Components Deferred Revenues (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Notes To Financial Statements [Abstract]
Deferred revenues - current	$ 356,109	$ 267,713
Deferred revenues - long-term	$ 11,739	$ 4,588

Balance Sheet Components Narrat

Balance Sheet Components Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Revenue recognized	$ 505,289	$ 385,267	$ 1,432,472	$ 1,052,090
Deferred Revenue
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred revenue	$ 125,600	$ 74,000	$ 313,400	$ 186,800

Equity Method Investments (Deta

Equity Method Investments (Details) - USD ($)	Feb. 07, 2018	Jul. 24, 2017	Jul. 25, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity method investments				$ 47,996,000		$ 47,996,000		$ 54,606,000
Net revenues				505,289,000	$ 385,267,000	1,432,472,000	$ 1,052,090,000
Loan repayment from equity investee						30,000,000	6,000,000
SDC
Schedule of Equity Method Investments [Line Items]
Ownership			17.00%
Payments to acquire		$ 12,800,000	$ 46,700,000
Additional ownership acquired		2.00%
Due from related parties				12,500,000		12,500,000		$ 14,300,000
Net revenues				$ 8,100,000	$ 10,600,000	$ 22,000,000	$ 14,200,000
SDC
Schedule of Equity Method Investments [Line Items]
Loan repayment from equity investee	$ 30,000,000
Maximum | SDC
Schedule of Equity Method Investments [Line Items]
Loan receivable		$ 30,000,000

Business Combinations (Details)

Business Combinations (Details) - Certain Distributors $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Business Acquisition [Line Items]
Cash consideration	$ 9.5
Net tangible liabilities	1.9
Intangibles acquired	8.2
Goodwill and intangible assets, net	$ 3.2

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Change in Carrying Value of Goodwill (Details) - Clear Aligner $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Roll Forward]
Balance as of December 31, 2017	$ 64,614
Adjustments	(542)
Balance as of September 30, 2018	$ 64,072

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, beginning balance	$ 68,114	$ 68,116
Accumulated Amortization	(29,321)	(24,404)
Accumulated Impairment Loss	(19,258)	(19,258)
Net Carrying Value, ending balance	$ 19,535	$ 24,454
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	15 years	15 years
Gross Carrying Amount, beginning balance	$ 7,100	$ 7,100
Accumulated Amortization	(1,873)	(1,769)
Accumulated Impairment Loss	(4,179)	(4,179)
Net Carrying Value, ending balance	$ 1,048	$ 1,152
Existing technology
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	13 years	13 years
Gross Carrying Amount, beginning balance	$ 12,600	$ 12,600
Accumulated Amortization	(5,127)	(4,704)
Accumulated Impairment Loss	(4,328)	(4,328)
Net Carrying Value, ending balance	$ 3,145	$ 3,568
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	11 years	11 years
Gross Carrying Amount, beginning balance	$ 33,500	$ 33,500
Accumulated Amortization	(16,078)	(14,681)
Accumulated Impairment Loss	(10,751)	(10,751)
Net Carrying Value, ending balance	$ 6,671	$ 8,068
Reacquired rights
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	3 years	3 years
Gross Carrying Amount, beginning balance	$ 7,500	$ 7,500
Accumulated Amortization	(3,604)	(1,356)
Accumulated Impairment Loss	0	0
Net Carrying Value, ending balance	$ 3,896	$ 6,144
Patents
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	8 years	8 years
Gross Carrying Amount, beginning balance	$ 6,796	$ 6,798
Accumulated Amortization	(2,126)	(1,504)
Accumulated Impairment Loss	0	0
Net Carrying Value, ending balance	$ 4,670	$ 5,294
Other
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (in years)	2 years	2 years
Gross Carrying Amount, beginning balance	$ 618	$ 618
Accumulated Amortization	(513)	(390)
Accumulated Impairment Loss	0	0
Net Carrying Value, ending balance	$ 105	$ 228

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Total Estimated Annual Future Amortization Expense for Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Disclosure Total Estimated Annual Future Amortization Expense For Acquired Intangible Assets [Abstract]
Remainder of 2018	$ 1,571
2,019	6,171
2,020	3,854
2,021	3,388
2,022	2,116
Thereafter	2,435
Net Carrying Value, ending balance	$ 19,535	$ 24,454

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment					$ 0
Amortization	$ 1,500,000	$ 1,500,000	$ 4,500,000	$ 4,700,000

Credit Facilities - Additional

Credit Facilities - Additional Information (Details) - USD ($)	Feb. 27, 2018	Sep. 30, 2018	Mar. 22, 2013
Line of Credit Facility [Line Items]
Line of credit, available borrowings	$ 200,000,000		$ 50,000,000
Current borrowing capacity	$ 50,000,000		$ 10,000,000
Outstanding borrowings		$ 0
Base Rate
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	0.50%
London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	1.00%
Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	0.25%
Minimum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	1.25%
Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	0.75%
Maximum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis Spread on Variable Rate	1.75%

Legal Proceedings - Narrative (

Legal Proceedings - Narrative (Details)	Nov. 14, 2017Lawsuitpatent
Lawsuit Against 3Shape AS
Loss Contingencies [Line Items]
Number of lawsuits/complaints	6
Patents Allegedly Infringed upon | patent	26
Violation Of Trade Laws 3Shape
Loss Contingencies [Line Items]
Number of lawsuits/complaints	2
Patent Infringement By 3Shape
Loss Contingencies [Line Items]
Number of lawsuits/complaints	4

Commitments and Contingencies M

Commitments and Contingencies Minimum Future Lease Payments for Non-Cancelable Leases (Details) - USD ($)	May 29, 2018	Feb. 07, 2018	Nov. 27, 2017	Jul. 24, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure Minimum Future Lease Payments For Non Cancelable Leases [Abstract]
Remainder of 2018					$ 4,839,000
2,019					19,131,000
2,020					15,988,000
2,021					14,386,000
2,022					12,026,000
Thereafter					25,769,000
Total minimum future lease payments					92,139,000
Other Commitments [Line Items]
Loan repayment from equity investee					$ 30,000,000	$ 6,000,000
Minimum purchase commitment	$ 425,900,000		$ 305,200,000
Purchase commitment, period	5 years		4 years
SDC
Other Commitments [Line Items]
Loan repayment from equity investee		$ 30,000,000
Maximum | SDC
Other Commitments [Line Items]
Loan facility				$ 30,000,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)shares
Incentive Plan 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	27,783,379
Number of shares available for issuance	6,063,095
Employee Stock Purchase Plan 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available	2,400,000
Number of shares remaining	571,778
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unamortized compensation cost | $	$ 90.1
Weighted average period of total unamortized cost (in years)	2 years 1 month 6 days
Market Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unamortized compensation cost | $	$ 44.6
Weighted average period of total unamortized cost (in years)	1 year 4 months 24 days
Market Performance Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of market-performance based restricted stock units eligible to vest over the vesting period	250.00%
Market Performance Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of granted market-performance based restricted stock units	3 years
Percentage of market-performance based restricted stock units eligible to vest over the vesting period	300.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unamortized compensation cost | $	$ 3.3
Weighted average period of total unamortized cost (in years)	7 months 6 days

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation Expense Related to All Stock-Based Awards and Employee Stock Purchases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 19,198	$ 14,967	$ 51,918	$ 44,024
Cost of net revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	966	833	2,747	2,526
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	15,403	11,880	41,197	34,814
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,829	$ 2,254	$ 7,974	$ 6,684

Stockholders' Equity - Activity

Stockholders' Equity - Activity Under Stock Option Plans (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Number of Shares Underlying Stock Options
Outstanding as of December 31, 2017 | shares	75
Exercised | shares	(63)
Cancelled or expired | shares	0
Outstanding as of September 30, 2018 | shares	12
Vested at September 30, 2018 | shares	12
Exercisable at September 30, 2018 | shares	12
Weighted Average Exercise Price per Share
Outstanding as of December 31, 2017 | $ / shares	$ 11.36
Exercised | $ / shares	11.99
Cancelled or expired | $ / shares	0
Outstanding as of September 30, 2018 | $ / shares	7.99
Vested at September 30, 2018 | $ / shares	7.99
Exercisable at September 30, 2018 | $ / shares	$ 7.99
Weighted Average Remaining Contractual Term
Outstanding as of September 30, 2018	4 months 28 days
Vested at September 30, 2018	4 months 28 days
Exercisable at September 30, 2018	4 months 28 days
Aggregate Intrinsic Value
Outstanding as of September 30, 2018 | $	$ 4,534
Vested at September 30, 2018 | $	4,534
Exercisable at September 30, 2018 | $	$ 4,534

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Nonvested Shares (Details) - Restricted Stock Units (RSUs) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Number of Shares Underlying RSUs
Nonvested as of December 31, 2017 | shares	1,341
Granted | shares	225
Vested and released | shares	(516)
Forfeited | shares	(74)
Nonvested as of September 30, 2018 | shares	976
Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2017 | $ / shares	$ 82.30
Granted | $ / shares	261.52
Vested and released | $ / shares	73.44
Forfeited | $ / shares	105.53
Nonvested as of September 30, 2018 | $ / shares	$ 126.52
Weighted Remaining Contractual Term (in years)
Nonvested as of September 30, 2018	1 year 2 months 23 days
Aggregate Intrinsic Value
Nonvested as of September 30, 2018 | $	$ 381,710

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of MSU Performance (Details) - Market Performance Based Restricted Stock Units $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Number of Shares Underlying MSUs
Nonvested as of December 31, 2017 | shares	428
Granted | shares	208
Vested and released | shares	(312)
Forfeited | shares	0
Nonvested as of September 30, 2018 | shares	324
Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2017 | $ / shares	$ 78.53
Granted | $ / shares	266.78
Vested and released | $ / shares	62.41
Forfeited | $ / shares	0
Nonvested as of September 30, 2018 | $ / shares	$ 215.07
Weighted Average Remaining Contractual Term (in years)
Nonvested as of September 30, 2018	1 year 4 months 28 days
Aggregate Intrinsic Value
Nonvested as of September 30, 2018 | $	$ 126,834

Stockholders' Equity - Stock-_2

Stockholders' Equity - Stock-based Compensation Employee Stock Purchase Plan (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected term (in years)	1 year 2 months 12 days	1 year 2 months 12 days	1 year 3 months 12 days	1 year 2 months 12 days
Expected volatility	35.70%	28.80%	35.20%	26.80%
Risk-free interest rate	2.50%	1.20%	2.20%	1.00%
Expected dividends	0.00%	0.00%	0.00%	0.00%
Weighted average fair value at grant date (USD per Share)	$ 109.58	$ 47.02	$ 94.71	$ 31.36

Common Stock Repurchase Progr_2

Common Stock Repurchase Programs - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended
	Aug. 31, 2018	Jul. 31, 2018	Feb. 28, 2018	Nov. 30, 2017	May 31, 2017	Jan. 31, 2017	May 23, 2018	Apr. 30, 2016
April 2014 Stock Repurchase Program
Share Repurchases [Line Items]
Accelerated share repurchase (shares)						40
Share repurchase price (in dollars per share)						$ 96.37
Repurchased						$ 3.8
April 2016 Repurchase Program
Share Repurchases [Line Items]
Accelerated share repurchase (shares)		300	400
Share repurchase price (in dollars per share)		$ 350.08	$ 252.24
Repurchased		$ 100	$ 100
Repurchase of common stock, common stock authorized								$ 300
2017 ASR
Share Repurchases [Line Items]
Accelerated share repurchase (shares)				200	400
Share repurchase price (in dollars per share)				$ 243.40
Price ($ per share)					$ 146.48
Repurchased				$ 50	$ 50
May 2018 Repurchase
Share Repurchases [Line Items]
Accelerated share repurchase (shares)	100
Share repurchase price (in dollars per share)	$ 356.54
Repurchased	$ 50
Repurchase of common stock, common stock authorized							$ 600
Remaining shares under repurchase program	$ 550

Accounting for Income Taxes - A

Accounting for Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	Aug. 21, 2018	Jun. 30, 2017	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Line Items]
Provision for income taxes			$ 24,601		$ 18,344	$ 35,206	$ 26,508
Effective income tax rate, continuing operations			19.40%		17.90%	10.20%	10.50%
Income Tax Expense (Benefit), Previously Unrecognized			$ 29,000			$ 29,000
Unrecognized Tax Benefits, Interest on Income Taxes Expense			2,900			2,900
Effective Income Tax Rate Reconciliation Share based Compensation Excess Tax Benefit Amount Accrual			14,700
Unrecognized tax benefits			27,100	$ 47,700		27,100		$ 47,700
Accrued penalties and interest			800			800
Extension period		12 years
Undistributed earnings of foreign subsidiaries				606,500				606,500
Amount of no longer indefinitely reinvested foreign earnings				591,900
Deferred tax liability due in event of foreign earnings being distributed				3,300
Amount of indefinitely reinvested foreign earnings				14,700				14,700
Additional income tax expense due to TCJA						$ 3,300		84,300
TCJA related to provisional transion tax liability				$ 73,900				73,900
TCJA related to remeasurement of certain deferred tax assets and liabilities								$ 10,400
Foreign Tax Authority
Income Taxes [Line Items]
Foreign income tax rate						30.00%	30.00%
Accounting Standards Update 2016-09
Income Taxes [Line Items]
Tax benefit, reversed	$ (20,200)		$ (20,200)			$ (20,200)
Effective Income Tax Rate Reconciliation Share based Compensation Excess Tax Benefit Amount						$ 25,200

Computation of Basic and Dilute

Computation of Basic and Diluted Net Income Per Share Attributable to Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 100,872	$ 82,555	$ 302,843	$ 221,154
Weighted-average common shares outstanding, basic	80,111	80,163	80,122	80,086
Dilutive effect of potential common stock	1,248	1,626	1,416	1,671
Total shares, diluted	81,359	81,789	81,538	81,757
Net income per share, basic	$ 1.26	$ 1.03	$ 3.78	$ 2.76
Net income per share, diluted	$ 1.24	$ 1.01	$ 3.71	$ 2.71

Segments and Geographical Inf_3

Segments and Geographical Information - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018segment
Disclosure Segments And Geographical Information Additional Information [Abstract]
Number of reportable segments	2

Segments and Geographical Inf_4

Segments and Geographical Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 505,289	$ 385,267	$ 1,432,472	$ 1,052,090
Gross profit	371,781	292,488	1,064,771	799,030
Income from operations	125,208	98,763	346,091	244,005
Interest income	2,234	1,826	6,327	4,462
Depreciation and amortization	14,119	9,972	38,185	26,715
Other income (expense), net	(837)	1,924	(7,759)	4,145
Net income before provision for income taxes and equity in losses of investee	126,605	102,513	344,659	252,612
Operating segments
Segment Reporting Information [Line Items]
Income from operations	214,165	168,139	599,658	431,588
Clear Aligner
Segment Reporting Information [Line Items]
Net revenues	427,087	341,611	1,245,833	945,046
Gross profit	321,772	266,285	950,360	737,046
Income from operations	182,667	154,614	534,408	403,264
Depreciation and amortization	7,218	5,643	20,361	15,607
Scanner
Segment Reporting Information [Line Items]
Net revenues	78,202	43,656	186,639	107,044
Gross profit	50,009	26,203	114,411	61,984
Income from operations	31,498	13,525	65,250	28,324
Depreciation and amortization	1,237	1,130	3,510	3,248
Unallocated corporate expenses
Segment Reporting Information [Line Items]
Income from operations	(88,957)	(69,376)	(253,567)	(187,583)
Depreciation and amortization	$ 5,664	$ 3,199	$ 14,314	$ 7,860

Segments and Geographical Inf_5

Segments and Geographical Information - Net Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 505,289	$ 385,267	$ 1,432,472	$ 1,052,090
United States
Segment Reporting Information [Line Items]
Net revenues	263,349	217,758	754,472	608,052
The Netherlands
Segment Reporting Information [Line Items]
Net revenues	141,405	109,068	437,364	318,399
China
Segment Reporting Information [Line Items]
Net revenues	52,874	26,965	116,891	59,195
Other International
Segment Reporting Information [Line Items]
Net revenues	$ 47,661	$ 31,476	$ 123,745	$ 66,444

Segments and Geographical Inf_6

Segments and Geographical Information - Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total long-lived assets	$ 491,630	$ 348,793
The Netherlands
Segment Reporting Information [Line Items]
Total long-lived assets	195,790	143,673
United States
Segment Reporting Information [Line Items]
Total long-lived assets	135,369	128,171
Costa Rica
Segment Reporting Information [Line Items]
Total long-lived assets	71,437	30,738
Mexico
Segment Reporting Information [Line Items]
Total long-lived assets	34,272	25,090
China
Segment Reporting Information [Line Items]
Total long-lived assets	33,955	5,480
Other International
Segment Reporting Information [Line Items]
Total long-lived assets	$ 20,807	$ 15,641