Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2017
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 contain all adjustments, including normal recurring adjustments, necessary to state fairly our results of operations for the three and six months ended June 30, 2017 and 2016, our comprehensive income for the three and six months ended June 30, 2017 and 2016, our financial position as of June 30, 2017 and our cash flows for the six months ended June 30, 2017 and 2016. The Condensed Consolidated Balance Sheet as of December 31, 2016 was derived from the December 31, 2016 audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States of America. The results of operations for the three and six months ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 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, 2016.
Use of estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles ("GAAP") in the United States of America (“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, long-lived assets and goodwill, equity method investments, useful lives of intangible assets and property and equipment, revenue recognition, stock-based compensation, equity losses of investee, 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements (i) New Accounting Updates Recently Adopted In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-09, "Improvements to Employee Share-Based Payment Accounting" (Topic 718). We adopted the standard in the first quarter of fiscal year 2017. With this adoption, excess tax benefits related to stock-based compensation expense are reflected in our condensed consolidated statement of operations as a component of the provision for income taxes instead of additional paid-in capital in our condensed consolidated balance sheet. During the six months ended June 30, 2017, we recognized excess tax benefits of $22.4 million in our provision for income taxes. Excess tax benefits from share-based payment arrangements are classified as an operating activity in our condensed consolidated statement of cash flows in the same manner as other cash flows related to income taxes. We have elected to apply the standard on a prospective basis. In addition, we elected to continue to estimate expected forfeitures rather than as they occur to determine the amount of compensation cost to be recognized in each period. In October 2016, the FASB issued ASU 2016-16, "Intra-Entity Transfers of Assets Other Than Inventory," (Topic 740) which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. We early adopted the standard in the first quarter of fiscal year 2017 by applying the modified retrospective approach. During the first quarter of fiscal year 2017, we recognized a $1.3 million decrease to retained earnings as a cumulative-effect adjustment. (ii) Recent Accounting Updates Not Yet Effective In May 2014, the FASB released ASU 2014-9, "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. The new standard defines a five step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than required under existing GAAP including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. In addition, the new standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. We plan to adopt the standard in the first quarter of fiscal year 2018 by applying the full retrospective method. Our ability to adopt using the full retrospective method is dependent on the completion of our analysis of information necessary to restate prior period financial statements. We are continuing to evaluate the accounting, transition and disclosure requirements of the standard and are in process of assessing the financial statement impact of adoption. In April 2016, the FASB released ASU 2016-10, "Revenue from Contracts with Customers," to clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the principles for those areas of the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606. In May 2016, the FASB released ASU 2016-12, "Revenue from Contracts with Customers," to address certain issues in the Topic 606 guidance on assessing the collectability, presentation of sales taxes, non-cash consideration, and completed contracts and contract modifications at transition. The ASU provides narrow-scope improvements and practical expedients to the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606. In December 2016, the FASB released ASU 2016-20, "Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers," to clarify certain aspects of guidance in the Topic 606 including its scope, disclosure requirements and contract cost accounting, while retaining the principles for those areas of the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606. In February 2016, the FASB issued ASU 2016-02, “Leases” (Topic 842). The FASB issued this update 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. Early adoption of the standard is permitted. We plan to adopt the standard in the first quarter of fiscal year 2019 by electing practical expedients available in the standard. While we 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 to the assets and liabilities of 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 as of the 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 August 2016, the FASB issued ASU 2016-15, "Classification of Certain Cash Receipts and Cash Payments" (Topic 230). This FASB 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. Early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. 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, and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business,” to clarify the definition of a business when evaluating whether transactions should be accounted for as acquisitions of assets or businesses. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 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 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 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, and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

Recent Accounting Pronouncements

(i) New Accounting Updates Recently Adopted

In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-09, "Improvements to Employee Share-Based Payment Accounting" (Topic 718). We adopted the standard in the first quarter of fiscal year 2017. With this adoption, excess tax benefits related to stock-based compensation expense are reflected in our condensed consolidated statement of operations as a component of the provision for income taxes instead of additional paid-in capital in our condensed consolidated balance sheet. During the six months ended June 30, 2017, we recognized excess tax benefits of $22.4 million in our provision for income taxes. Excess tax benefits from share-based payment arrangements are classified as an operating activity in our condensed consolidated statement of cash flows in the same manner as other cash flows related to income taxes. We have elected to apply the standard on a prospective basis. In addition, we elected to continue to estimate expected forfeitures rather than as they occur to determine the amount of compensation cost to be recognized in each period.

In October 2016, the FASB issued ASU 2016-16, "Intra-Entity Transfers of Assets Other Than Inventory," (Topic 740) which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. We early adopted the standard in the first quarter of fiscal year 2017 by applying the modified retrospective approach. During the first quarter of fiscal year 2017, we recognized a $1.3 million decrease to retained earnings as a cumulative-effect adjustment.

(ii) Recent Accounting Updates Not Yet Effective

In May 2014, the FASB released ASU 2014-9, "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. The new standard defines a five step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than required under existing GAAP including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. In addition, the new standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. We plan to adopt the standard in the first quarter of fiscal year 2018 by applying the full retrospective method. Our ability to adopt using the full retrospective method is dependent on the completion of our analysis of information necessary to restate prior period financial statements. We are continuing to evaluate the accounting, transition and disclosure requirements of the standard and are in process of assessing the financial statement impact of adoption.

In April 2016, the FASB released ASU 2016-10, "Revenue from Contracts with Customers," to clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the principles for those areas of the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606.

In May 2016, the FASB released ASU 2016-12, "Revenue from Contracts with Customers," to address certain issues in the Topic 606 guidance on assessing the collectability, presentation of sales taxes, non-cash consideration, and completed contracts and contract modifications at transition. The ASU provides narrow-scope improvements and practical expedients to the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606.

In December 2016, the FASB released ASU 2016-20, "Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers," to clarify certain aspects of guidance in the Topic 606 including its scope, disclosure requirements and contract cost accounting, while retaining the principles for those areas of the ASU 2014-9 issued in May 2014. The effective date and the transition requirement of the amendments in this update are the same as the effective date and transition requirements of Topic 606.

In February 2016, the FASB issued ASU 2016-02, “Leases” (Topic 842). The FASB issued this update 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. Early adoption of the standard is permitted. We plan to adopt the standard in the first quarter of fiscal year 2019 by electing practical expedients available in the standard. While we 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 to the assets and liabilities of 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 as of the 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 August 2016, the FASB issued ASU 2016-15, "Classification of Certain Cash Receipts and Cash Payments" (Topic 230). This FASB 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. Early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

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, and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business,” to clarify the definition of a business when evaluating whether transactions should be accounted for as acquisitions of assets or businesses. The amendments are effective for fiscal years and interim periods within those years beginning after December 15, 2017 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 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 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, and early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.