Align Technology (ALGN) 10-K 26 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 20, 2015	Jun. 30, 2014
Document Documentand Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	ALGN
Entity Registrant Name	ALIGN TECHNOLOGY INC
Entity Central Index Key	1097149
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (shares)		80,720,243
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$4,457,461,725
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement [Abstract]
Net revenues	$761,653	[1]	$660,206	[1]	$560,041	[1]
Cost of revenues	183,210		162,100		143,653
Gross profit	578,443		498,106		416,388
Operating expenses:
Sales and marketing	217,262		180,046		152,041
General and administrative	114,806		112,752		99,295
Research and development	52,799		44,083		42,869
Impairment of goodwill	0		40,693		36,591
Impairment of long lived assets	0		26,320		0
Total operating expenses	384,867		403,894		330,796
Income from operations	193,576		94,212		85,592
Interest and other income (expense), net	-3,207		-1,073		-1,296
Net income before provision for income taxes	190,369		93,139		84,296
Provision for income taxes	44,537		28,844		25,605
Net income	$145,832		$64,295		$58,691
Net income per share:
Basic (usd per share)	$1.81		$0.80		$0.73
Diluted (usd per share)	$1.77		$0.78		$0.71
Shares used in computing net income per share:
Basic (shares)	80,754		80,551		80,529
Diluted (shares)	82,283		82,589		83,040
[1]	2 Long-lived assets are attributed to countries based on entity that owns the assets.

CONSOLIDATED_STATEMENT_OF_COMP

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$145,832	$64,295	$58,691
Net change in cumulative translation adjustment	-196	62	129
Change in unrealized gains (losses) on available-for sale securities, net of tax	-238	29	28
Other comprehensive income (loss)	-434	91	157
Comprehensive income (loss)	$145,398	$64,386	$58,848

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$199,871	$242,953
Marketable securities, short-term	254,787	127,040
Accounts receivable, net of allowance for doubtful accounts and returns of $1,563 and $1,733, respectively	129,751	113,250
Inventories	15,928	13,968
Prepaid expenses and other current assets	19,770	18,829
Deferred Tax Assets, Net, Current	37,053	28,636
Total current assets	657,160	544,676
Marketable securities, long-term	147,892	101,978
Property, plant and equipment, net	90,125	75,743
Goodwill	82,056	85,362
Deferred tax assets	3,099	15,766
Other assets	7,665	8,622
Total assets	987,997	832,147
Current liabilities:
Accounts payable	23,247	17,718
Accrued liabilities	87,880	80,345
Deferred revenues	90,684	77,275
Total current liabilities	201,811	175,338
Taxes Payable	30,483	18,326
Other long-term liabilities	2,932	4,513
Total liabilities	235,226	198,177
Commitments and contingencies (Notes 6 and 8)
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; 80,205 and 80,583 issued and outstanding at 2014 and 2013, respectively)	8	8
Additional paid-in capital	783,410	729,578
Accumulated other comprehensive income, net	-140	294
Accumulated deficit	-30,507	-95,910
Total stockholders' equity	752,771	633,970
Total liabilities and stockholders' equity	$987,997	$832,147

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts and returns	$1,563	$1,733
Preferred stock, par value (usd per share)	$0.00	$0.00
Preferred stock, shares authorized (shares)	5,000	5,000
Preferred stock, issued (shares)
Common stock, par value (usd per share)	$0.00	$0.00
Common stock, shares authorized (shares)	200,000	200,000
Common stock, issued (shares)	80,205	80,583
Common stock, outstanding (shares)	80,205	80,583

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
In Thousands, unless otherwise specified
Beginning Balance at Dec. 31, 2011	$490,781	$8	$607,240	$46	($116,513)
Beginning Balance (in shares) at Dec. 31, 2011		78,776
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	58,691				58,691
Net change in unrealized gain (loss) from available-for sale securities	28			28
Net change in cumulative translation adjustment	129			129
Issuance of common stock relating to employee equity compensation plans (in shares)		3,565
Issuance of common stock relating to employee equity compensation plans	42,327	0	42,327
Tax withholdings related to net share settlements of restricted stock units	-2,106		-2,106
Common stock repurchased and retired (shares)		-1,730
Common stock repurchased and retired	-47,203		-15,399		-31,804
Excess tax benefit from share based payment arrangements	17,187		17,187
Stock based compensation	21,483		21,483
Ending Balance at Dec. 31, 2012	581,317	8	670,732	203	-89,626
Ending Balance (in shares) at Dec. 31, 2012		80,611
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	64,295				64,295
Net change in unrealized gain (loss) from available-for sale securities	29			29
Net change in cumulative translation adjustment	62			62
Issuance of common stock relating to employee equity compensation plans (in shares)		2,694
Issuance of common stock relating to employee equity compensation plans	34,196	0	34,196
Tax withholdings related to net share settlements of restricted stock units	-4,363		-4,363
Common stock repurchased and retired (shares)		-2,722
Common stock repurchased and retired	-95,107		-24,528		-70,579
Excess tax benefit from share based payment arrangements	27,103		27,103
Stock based compensation	26,438		26,438
Ending Balance at Dec. 31, 2013	633,970	8	729,578	294	-95,910
Ending Balance (in shares) at Dec. 31, 2013		80,583
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	145,832				145,832
Net change in unrealized gain (loss) from available-for sale securities	-238			-238
Net change in cumulative translation adjustment	-196			-196
Issuance of common stock relating to employee equity compensation plans (in shares)		1,536
Issuance of common stock relating to employee equity compensation plans	18,028		18,028
Tax withholdings related to net share settlements of restricted stock units	-7,608		-7,608
Common stock repurchased and retired (shares)		-1,914
Common stock repurchased and retired	-98,233		-17,804		-80,429
Excess tax benefit from share based payment arrangements	21,393		21,393
Stock based compensation	39,823		39,823
Ending Balance at Dec. 31, 2014	$752,771	$8	$783,410	($140)	($30,507)
Ending Balance (in shares) at Dec. 31, 2014		80,205

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$145,832	$64,295	$58,691
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred taxes	25,481	21,204	17,783
Depreciation and amortization	17,856	16,825	17,811
Stock-based compensation	39,823	26,438	21,483
Excess tax benefit from share-based payment arrangements	-21,393	-27,103	-17,187
Impairment of goodwill	0	40,693	36,591
Impairment of long lived assets	0	26,320	0
Other	10,106	4,142	4,517
Changes in assets and liabilities, excluding the effects of business combinations:
Accounts receivable	-27,229	-11,981	-11,666
Inventories	-1,999	1,158	-5,718
Prepaid expenses and other assets	-2,924	-392	-3,853
Accounts payable	2,887	-186	-6
Accrued and other long-term liabilities	22,692	9,662	2,943
Deferred revenues	15,767	14,901	12,389
Net cash provided by operating activities	226,899	185,976	133,778
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition, net of cash acquired	0	-7,652	0
Purchase of property, plant and equipment	-24,092	-19,412	-38,333
Purchase of marketable securities	-437,152	-303,917	-67,511
Proceeds from maturities of marketable securities	176,810	90,917	24,901
Proceeds from Sale and Maturity of Marketable Securities	82,990	31,741	297
Other assets	-183	-2,411	2,346
Net cash used in investing activities	-201,627	-210,734	-78,300
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	18,028	34,196	42,327
Common stock repurchase	-98,233	-95,107	-47,203
Excess tax benefit from share-based payment arrangements	21,393	27,103	17,187
Employees' taxes paid upon the vesting of restricted stock units	-7,608	-4,363	-2,106
Net cash (used in) provided by financing activities	-66,420	-38,171	10,205
Effect of foreign exchange rate changes on cash and cash equivalents	-1,934	-504	28
Net (decrease) increase in cash and cash equivalents	-43,082	-63,433	65,711
Cash and cash equivalents, beginning of year	242,953	306,386	240,675
Cash and cash equivalents, end of year	$199,871	$242,953	$306,386

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Business Description
	Align Technology, Inc. (“We”, “Our”, or “Align”) was incorporated in April 1997 in Delaware and focuses on designing, manufacturing and marketing innovative, technology-rich products to help dental professionals achieve the clinical results they expect and deliver effective, convenient cutting-edge dental treatment options to their patients. We are headquartered in San Jose, California with offices worldwide.  Our international headquarters are located in Amsterdam, the Netherlands. We have two operating segments, (1) Clear Aligner, known as the Invisalign System, and (2) Scanners and Services ("Scanner"), known as the iTero intra-oral scanner and OrthoCAD services.
	Basis of presentation and preparation
	The consolidated financial statements include the accounts of Align and our wholly-owned subsidiaries after elimination of intercompany transactions and balances.  Certain amounts in prior periods have been reclassified to conform with the current period presentation. These reclassifications had no impact on previously reported gross profit or financial position.
	In connection with the preparation of the consolidated financial statements, we evaluated events subsequent to the balance sheet date through the financial statement issuance date and determined that all material transactions have been recorded and disclosed properly.
	Out of period adjustment
	In 2013, we recorded an out of period correction that resulted in decreases in cost of net revenues of approximately $1.7 million and operating expense of $0.7 million offset in part by an increase in the provision for income taxes of $0.5 million. We do not believe the increase of $1.9 million to net income related to the out of period adjustment is material to the consolidated financial statements for the fiscal year ended December 31, 2013 or to any prior years' consolidated financial statements.
	In 2014, we recorded an out of period correction that resulted in an increase in the provision for income taxes of $1.8 million. We do not believe the decrease to net income related to the out of period adjustment is material to the consolidated financial statements for the fiscal year ended December 31, 2014 or to any prior years' consolidated financial statements.
	Use of estimates
	The preparation of financial statements in conformity with accounting principles generally accepted 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, intangible assets and goodwill, useful lives of intangible assets and property and equipment, stock-based compensation, revenue recognition, 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.
	Fair value of financial instruments
	The carrying amounts of our cash, accounts receivable, accounts payable and other current liabilities approximate their fair value.
	We measure our cash equivalents, marketable securities, and our Israeli severance fund at fair value.  Fair value is 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.  Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement:
	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.
	Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.
	Cash and cash equivalents
	We consider currency on hand, demand deposits, time deposits, and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents.  Cash and cash equivalents are held in various financial institutions in the U.S. and internationally.
	Restricted cash
	Our restricted cash balance as of December 31, 2014 was $3.8 million, of which $3.6 million was classified as a long term asset and $0.2 million as a current asset. Our restricted cash balance as of December 31, 2013 was $4.0 million and was classified as a long term asset. The restricted cash primarily consisted of funds reserved for legal requirements.
	Marketable securities
	We invest primarily in money market funds, commercial paper, corporate bonds, U.S. government agency bonds, asset-backed securities, municipal bonds, U.S. dollar dominated foreign corporate bonds, U.S. government treasury bonds and certificates of deposits.
	Marketable securities are classified as available-for-sale and are carried at fair value.  Marketable securities classified as current assets have maturities of less than one year.  Unrealized gains or losses on such securities are included in accumulated other comprehensive income, net in stockholders’ equity.  Realized gains and losses from maturities of all such securities are reported in earnings and computed using the specific identification cost method.  Realized gains or losses and charges for other-than-temporary declines in value, if any, on available-for-sale securities are reported in Interest and other income (expense), net as incurred.  We periodically evaluate these investments for other-than-temporary impairment.
	Foreign currency
	For our international subsidiaries where the U.S. dollar is the functional currency, we analyze on an annual basis or more often if necessary, if a significant change in facts and circumstances indicate that the primary economic currency has changed.  Adjustments from translating certain European and Asia Pacific subsidiaries’ financial statements from the local currency to the U.S. dollar are recorded as a separate component of accumulated other comprehensive income (loss), net in the stockholders’ equity section of the Consolidated Balance Sheet.  This foreign currency translation adjustment reflects the translation of the balance sheet at period end exchange rates, and the income statement at an average exchange rate in effect during the period.  As of December 31, 2014 and 2013, there were no material amounts in accumulated other comprehensive income, net related to the translation of our foreign subsidiaries’ financial statements.
	Our other international entities operate in a U.S. dollar functional currency environment, and therefore, the foreign currency assets and liabilities are remeasured into the U.S. dollar at current exchange rates except for non-monetary assets and liabilities which are remeasured at historical exchange rates.  Revenues and expenses are generally remeasured at an average exchange rate in effect during each period.  Gains or losses from foreign currency remeasurement are included in Interest and other income (expense), net. For the year ended December 31, 2014, we had foreign currency net losses of $3.8 million. For year ended December 31, 2013, foreign currency gains and losses were not significant.
	Certain risks and uncertainties
	Our operating results depend to a significant extent on our ability to market and develop our products.  The life cycles of our products are difficult to estimate due, in part, to the effect of future product enhancements and competition.  Our inability to successfully develop and market our products as a result of competition or other factors would have a material adverse effect on our business, financial condition and results of operations.
	Our cash and investments are held primarily by two financial institutions. Financial instruments which potentially expose us to concentrations of credit risk consist primarily of cash equivalents, marketable securities and accounts receivable.  We invest excess cash primarily in money market funds of major financial institutions, U.S. government agencies, U.S. dollar dominated foreign corporate bonds and domestic corporate bonds.  If the carrying value of our investments exceeds the fair value, and the decline in fair value is deemed to be other-than-temporary, we will be required to write down the value of our investments, which could materially harm our results of operations and financial condition.  Moreover, the performance of certain securities in our investment portfolio correlates with the credit condition of the U.S. economy.  We provide credit to customers in the normal course of business.  Collateral is not required for accounts receivable, but ongoing evaluations of customers’ credit worthiness are performed.  We maintain reserves for potential credit losses and such losses have been within management’s expectations.  No individual customer accounted for 10% or more of our accounts receivable at December 31, 2014 or 2013, or net revenues for the year ended December 31, 2014, 2013, or 2012.
	In the U.S., the Food and Drug Administration (“FDA”) regulates the design, manufacture, distribution, pre-clinical and clinical study, clearance and approval of medical devices.  Products developed by us may require approvals or clearances from the FDA or other international regulatory agencies prior to commercialized sales.  There can be no assurance that our products will receive any of the required approvals or clearances.  If we were denied approval or clearance or such approval was delayed, it may have a material adverse impact on us.
	We have manufacturing operations located outside the U.S.  We currently rely on our manufacturing facility in Costa Rica to prepare digital treatment plans using a sophisticated, internally developed computer-modeling program.  In addition, we manufacture our clear aligners and distribute our intra-oral scanners at our facility in Juarez, Mexico, and we produce our handheld scanner wand in Or Yehuda, Israel.  Our reliance on international operations exposes us to related risks and uncertainties, including difficulties in staffing and managing international operations such as hiring and retaining qualified personnel; controlling production volume and quality of manufacture; political, social and economic instability, particularly as a result of increased levels of violence in Juarez, Mexico and Israel; interruptions and limitations in telecommunication services; product and material transportation delays or disruption; trade restrictions and changes in tariffs; import and export license requirements and restrictions; fluctuations in foreign currency exchange rates; and potential adverse tax consequences.  If any of these risks materialize, our international manufacturing operations, as well as our operating results, may be harmed.
	We purchase certain inventory from sole suppliers.  Additionally, we rely on a limited number of hardware manufacturers.  The inability of any supplier or manufacturer to fulfill our supply requirements could materially and adversely impact our future operating results.
	Inventories
	Inventories are valued at the lower of cost or market, with cost computed using either standard cost (which approximates actual cost) or average and actual cost on a first-in-first-out basis.  Excess and obsolete inventories are determined primarily based on future demand forecasts, and write-downs of excess and obsolete inventories are recorded as a component of cost of revenues.
	Property, plant and equipment
	Property, plant and equipment are stated at historical cost less accumulated depreciation and amortization.  Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, generally three to ten years. We amortize leasehold improvements over the shorter of the remaining lease term or the estimated useful lives of the assets. We depreciate buildings over periods up to 20 years. Land is not depreciated. Construction in progress ("CIP") is related to the construction or development of property (including land) and equipment that have not yet been placed in service for their intended use.  Upon sale or retirement, the asset’s cost and related accumulated depreciation are removed from the general ledger and any related gains or losses are reflected in operating expenses.  Maintenance and repairs are expensed as incurred.
	Goodwill and finite-lived acquired intangible assets
	Goodwill represents the excess of the purchase price paid over the fair value of tangible and identifiable intangible net assets acquired in business combinations and is allocated to the respective reporting units based on relative synergies generated.
	Our intangible assets primarily consist of intangible assets acquired as part of the Cadent acquisition.  These assets are amortized using the straight-line method over their estimated useful lives ranging from one to fifteen years, reflecting the period in which the economic benefits of the assets are expected to be realized.
	Impairment of goodwill and long-lived assets
	Goodwill
	We evaluate goodwill for impairment at least annually on November 30th or more frequently if indicators are present, an event occurs or circumstances changes that suggest an impairment may exist and that it would more likely than not reduce the fair value of a reporting unit below its carrying amount.  The allocation of goodwill to the respective reporting unit is based on relative synergies generated as a result of an acquisition.
	We perform an initial assessment of qualitative factors to determine whether the existence of events and circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. In performing the qualitative assessment, we identify and consider the significance of relevant key factors, events, and circumstances that affect the fair value of our reporting units. These factors include external factors such as macroeconomic, industry, and market conditions, as well as entity-specific factors, such as our actual and planned financial performance. We also give consideration to the difference between the reporting unit fair value and carrying value as of the most recent date a fair value measurement was performed. If, after assessing the totality of relevant events and circumstances, we determine that it is more likely than not that the fair value of the reporting unit exceeds its carrying value and there is no indication of impairment, no further testing is performed; however, if we conclude otherwise, the first step of the two-step impairment test is performed by estimating the fair value of the reporting unit and comparing it with its carrying value, including goodwill.
	Step one of the goodwill impairment test consists of a comparison of the fair value of a reporting unit against its carrying amount, including the goodwill allocated to each reporting unit.  We determine the fair value of our reporting units based on the present value of estimated future cash flows under the income approach of the reporting units as well as various price or market multiples applied to the reporting unit's operating results along with the appropriate control premium under the marketing approach, both of which are classified as level 3 within the fair value hierarchy (as described in Note 2 in our consolidated financial statements).  If the carrying amount of the reporting unit is in excess of its fair value, step two requires the comparison of the implied fair value of the reporting unit’s goodwill against the carrying amount of the reporting unit’s goodwill.  Any excess of the carrying value of the reporting unit’s goodwill over the implied fair value of the reporting unit’s goodwill is recorded as an impairment loss.
	During March 2013, changes in the competitive environment for intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists ("GPs") in North America, caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that goodwill related only to our Scanner reporting unit should be tested for impairment as of March 31, 2013 due to these facts and circumstances which would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. There was no triggering event related to the Clear Aligner goodwill. Refer to Note 5 for details of the impairment analysis.
	The remaining goodwill is entirely attributable to our Clear Aligner reporting unit. During the fourth quarter of fiscal 2014, we performed the annual goodwill impairment testing using the qualitative approach discussed above and found no impairment as the fair value of our Clear Aligner reporting unit was significantly in excess of the carrying value.
	Finite-lived intangible assets and long-lived assets
	We evaluate long-lived assets (including finite-lived intangible assets) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable.  An asset or asset group is considered impaired if its carrying amount exceeds the future undiscounted net cash flows the asset or asset group is expected to generate.  If an asset or asset group is considered to be impaired, the impairment to be recognized is calculated as the amount by which the carrying amount of the asset or asset group exceeds its fair market value.  Our estimates of future cash flows attributable to our long-lived assets require significant judgment based on our historical and anticipated results and are subject to many factors. Factors we consider important which could trigger an impairment review include significant negative industry or economic trends, significant loss of customers and changes in the competitive environment. In 2013, we used a DCF approach, utilizing harvest model, to estimate the fair value of a reporting unit, which we believe is the most reliable indicator of fair value of a business, and is most consistent with the approach of a marketplace participant would use. The estimation of fair value utilizing a DCF approach includes numerous uncertainties which require our significant judgment when making assumptions of expected growth rates and the selection of discount rates, as well as assumptions regarding general economic and business conditions, and the structure that would yield the highest economic value, among other factors. Key assumptions used in measuring the fair values of Scanner reporting unit included the discount rate (based on the weighted-average cost of capital) and revenue growth. The fair value of Scanner’s trademark was determined using a risk-adjusted DCF model under the relief-from-royalty method. The royalty rate used was based on a consideration of market rates. The fair value of Scanner’s finite-lived customer relationships was determined using a DCF model under the multi-period excess earnings method. We recorded a long-lived asset impairment in the quarter ended March 31, 2013 due to changes in the competitive environment for our intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists in North America. There was no triggering event related to the Clear Aligner asset group. Refer to Note 5 for details of the impairment analysis.
	There were no further triggering events in 2014 that would cause further impairments of our long-lived assets.
	Development costs for internal use software
	Internally developed software includes enterprise-level business software that we are customizing to meet our specific operational needs. Such capitalized costs include external direct costs utilized in developing or obtaining the applications and payroll and payroll-related costs for employees, who are directly associated with the development of the applications. In 2014, we started an enterprise resource planning ("ERP") project which we have capitalized $2.6 million of costs as of December 31, 2014 which is included in construction in progress ("CIP"). When the ERP is placed into production, these costs will be amortized over 10 years. Internal development costs for internal use software for 2013 were not material.
	The costs to develop software that is marketed externally have not been capitalized as we believe our current software development process is essentially completed concurrent with the establishment of technological feasibility. As such, all related software development costs are expensed as incurred and included in research and development expense in our consolidated statement of operations.
	Product Warranty
	Clear Aligner
	We warrant our Invisalign products against material defects until the Invisalign case is complete. We accrue for warranty costs in cost of net revenues upon shipment of products. The amount of accrued estimated warranty costs is primarily based on historical experience as to product failures as well as current information on replacement costs.  Actual warranty costs could differ materially from the estimated amounts. We regularly review the accrued balances and update these balances based on historical warranty cost trends.
	Scanners and Services
	We warrant our intra-oral scanners for a period of one year, which include materials and labor.  We accrue for these warranty costs based on average historical repair costs.  An extended warranty may be purchased for additional fees.
	Allowance for Doubtful Accounts and Returns
	We maintain allowances for doubtful accounts, for customers that are not able to make payments, and for sales returns.  We periodically review these allowances, including an analysis of the customers’ payment history and information regarding the customers’ creditworthiness, as well as historical sales returns as a percentage of revenue.  Actual write-offs have not materially differed from the estimated allowance.
	Revenue Recognition
	We measure and allocate revenue according to the accounting guidance for multiple-deliverable revenue arrangements in Accounting Standards Update (“ASU”) 2009-13, Multiple-Deliverable Revenue Arrangements-a consensus of the Financial Accounting Standard Board (“FASB”) Emerging Issues Task Force.
	Multiple-Element Arrangements (“MEAs”): Arrangements with customers may include multiple deliverables, including any combination of products/equipment and services.  The deliverables included in the MEAs are separated into more than one unit of accounting when (i) the delivered product/equipment has value to the customer on a stand-alone basis, and (ii) delivery of the undelivered service element(s) is probable and substantially in our control.  Arrangement consideration is then allocated to each unit, delivered or undelivered, based on the relative selling price (“RSP”) of each unit of accounting based first on vendor-specific objective evidence (“VSOE”) if it exists, second on third-party evidence (“TPE”) if it exists, and on best estimated selling price (“BESP”) if neither VSOE or TPE exist.
	•	VSOE – In most instances, products are sold separately in stand-alone arrangements.  Services are also sold separately through renewals of contracts with varying periods.  We determine VSOE based on its pricing and discounting practices for the specific product or service when sold separately, considering geographical, customer, and other economic or marketing variables, as well as renewal rates or stand-alone prices for the service element(s).
•	TPE – If we cannot establish VSOE of selling price for a specific product or service included in a multiple-element arrangement, we use third-party evidence of selling price. We determine TPE based on sales of comparable amount of similar products or service offered by multiple third parties considering the degree of customization and similarity of product or service sold.
•	BESP – The best estimated selling price represents the price at which we would sell a product or service if it were sold on a stand-alone basis.  When VSOE or TPE do not exist for all elements, we determine BESP for the arrangement element based on sales, cost and margin analysis, as well as other inputs based on its pricing practices.  Adjustments for other market and Company-specific factors are made as deemed necessary in determining BESP.
Provisions for discounts and rebates to customers are provided for in the same period that the related product sales are recorded based upon historical discounts and rebates.
Clear Aligner
We enter into arrangements (“treatment plans”) that involve multiple future product deliverables.  Invisalign Full, Invisalign Teen, and Invisalign Assist include up to three optional case refinements. Case refinement is a finishing tool used to adjust a patient's teeth to the desired final position.  Case refinement may be elected by the dental professional at any time during treatment however it is generally ordered in the last stages of orthodontic treatment.  Beginning June 15, 2013, Invisalign Full and Invisalign Teen also include up to three optional mid-course corrections. Mid-course correction is a treatment adjustment during active treatment if the case is not tracking to the original treatment plan or goals. Mid-course correction gives doctors the ability to "adjust course' based on the needs of the individual patient. Invisalign Teen also includes up to six optional replacement aligners in the price of the product and may be ordered any time throughout treatment.
We determined that our treatment plans, except Invisalign Assist with progress tracking, comprise the following deliverables which also represent separate units of accounting: single-batched aligners, case refinement, mid-course correction and replacement aligners.  We allocate revenue for each treatment plan based on each unit's relative selling price based on BESP and recognize the revenue upon the delivery of each unit in the treatment plan. We regularly review our estimates of selling price and maintain internal controls over the establishment and update of these estimates.
For Invisalign Assist with the progress tracking feature, aligners and services are provided to the dental professional every nine stages (“a batch”). We estimate the number of batches which are expected to be shipped for each case based upon our historical experience.  The amounts allocated to this deliverable are recognized on a prorated basis as each batch is shipped.
Prior to 2013, the Vivera Retainer included four shipments per year, and revenue was recognized ratably as each shipment occurred. In the first quarter of 2013, we consolidated Vivera Retainer product shipments down to one shipment per year.
Scanners and Services
We recognize revenues from the sales of iTero intra-oral scanners and CAD/CAM services. CAD/CAM services include scanning services, extended warranty for the intra-oral scanners, a range of iTero restorative services, and OrthoCAD services such as OrthoCAD iRecord. We sell intra-oral scanners and services through both our direct sales force and distribution partners.  The intra-oral scanner sales price includes one year of warranty, and for additional fees, the customer may select an unlimited scanning service agreement over a fixed period of time or extended warranty periods.  Revenue is recognized when persuasive evidence of the arrangement exists, the price is fixed or determinable, collectability is reasonably assured, title and risk of loss has passed to customers based on the shipping terms, no significant obligations remain, and allowances for discounts, returns, and customer incentives can be reliably estimated. When intra-oral scanners are sold with either an unlimited scanning service agreement and/or extended warranty, we allocate revenue based on each element's relative selling price.  We estimate the selling price of each element, as if it is sold on a stand-alone basis, taking into consideration historical prices as well as our discounting strategies. Scanner revenue, net of related discounts and allowances, is recognized when products or equipment have been shipped, installed and on-site training completed.   For certain distributors who provide installation and training to the customer, we recognize scanner revenue when the intra-oral scanner is shipped to the distributor assuming all of the other revenue recognition criteria have been met.
Discounts are deducted from revenue at the time of sale or when the discount is offered, whichever is later, and free cases or training is included as a deliverable in the multiple-element arrangement assessment. Returns of products, excluding warranty related returns, are infrequent and insignificant.
Service revenue, including iTero restorative and all OrthoCAD services are recognized upon delivery or ratably over the contract term as the specified services are performed. If a customer selects a pay per use basis for scanning service fees, the revenue is recognized as the service is provided.
We offer customers an option to purchase extended warranties on certain products. We recognize revenue on these extended warranty contracts ratably over the life of the contract. The costs associated with these extended warranty contracts are recognized when incurred.
Shipping and Handling Costs
Shipping and handling charges to customers are included in net revenues, and the associated costs incurred are recorded in cost of revenues.
Legal Proceedings and Litigations
We are involved in legal proceedings on an ongoing basis. If we believe that a loss arising from such matters is probable and can be reasonably estimated, we accrue the estimated liability in our financial statements. If only a range of estimated losses can be determined, we accrue an amount within the range that, in our judgment, reflect the most likely outcome; if none of the estimates within that range is a better estimate than any other amount, we accrue the low end of the range.
Research and development
Research and development expense is expensed as incurred and includes the costs associated with the research and development of new products and enhancements to existing products. These costs primarily include compensation costs, including stock-based compensation expense, outside consulting expenses, costs associated with conducting clinical and pre-commercialization trial and testing, allocations of corporate overhead expenses including facilities and IT costs, equipment costs and depreciation and amortization.
Advertising costs
The cost of advertising and media is expensed as incurred. For the year ended December 31, 2014, 2013 and 2012 advertising costs totaled $26.9 million, $26.0 million and $23.6 million, respectively.
Common stock repurchase
We repurchase our own common stock from time to time in the open market when our Board of Directors approve a stock repurchase program. We account for these repurchases under the accounting guidance for equity where we allocate the total repurchase value that are in excess over par between additional paid in capital and retained earnings. All shares repurchased are retired.
Operating leases
We currently lease office spaces, automobiles and equipment under operating leases with original lease periods of up to 9 years.  Certain of these leases have free or escalating rent payment provisions and lease incentives provided by the landlord. We recognize rent expense under such leases on a straight-line basis over the term of the lease as certain leases have adjustments for market provisions.
Income taxes
We make certain estimates and judgments in determining income tax expense for financial statement purposes. These estimates and judgments occur in the calculation of certain tax assets and liabilities, which arise from differences in the timing of recognition of revenue and expense for tax and financial statement purposes.
As part of the process of preparing our Consolidated Financial Statements, we are required to estimate our income taxes in each of the jurisdictions in which we operate. This process involves us estimating our current tax exposure under the applicable tax laws and assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included in our Consolidated Balance Sheets.
We account for uncertainty in income taxes pursuant to authoritative guidance based on a two-step approach to recognize and measure uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained on audit based on its technical merits, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement. We adjust reserves for our uncertain tax positions due to changing facts and circumstances, such as the closing of a tax audit, or refinement of estimates due to new information. To the extent that the final outcome of these matters is different than the amounts recorded, such differences will impact our tax provision in our Consolidated Statements of Operations in the period in which such determination is made.
We assess the likelihood that we will be able to realize our deferred tax assets. Should there be a change in our ability to realize our deferred tax assets, our tax provision would increase in the period in which we determine that it is more likely than not that we cannot realize our deferred tax assets. We consider all available evidence, both positive and negative, including historical levels of income, expectations and risks associated with estimates of future taxable income and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. If it is more likely than not that we will not realize our deferred tax assets, we will increase our provision for taxes by recording a valuation allowance against the deferred tax assets that we estimate will not ultimately be realizable. The available positive evidence at December 31, 2014 included historical operating profits and a projection of future income sufficient to realize most of our remaining deferred tax assets. As of December 31, 2014, it was considered more likely than not that our deferred tax assets would be realized with the exception of certain foreign loss carryovers as we are unable to forecast sufficient future profits to realize the deferred tax assets.
As of December 31, 2014, U.S. income taxes and foreign withholding taxes associated with the repatriation of undistributed earnings of foreign subsidiaries were not provided for on a cumulative total of $260.9 million. We intend to reinvest these earnings indefinitely in our foreign subsidiaries. If these earnings were distributed in the form of dividends or otherwise, or if the shares of the relevant foreign subsidiaries were sold or otherwise transferred, we would be subject to additional U.S. income taxes subject to an adjustment for foreign tax credit, and foreign withholding taxes. Determination of the amount of unrecognized deferred income tax liability related to these earnings is not practicable.
Accounting guidance for stock-based compensation prohibits recognition of a deferred income tax asset for excess tax benefits due to stock option exercises that have not yet been realized through a reduction in income taxes payable. We follow the tax law ordering method to determine when excess tax benefits have been realized and consider only the direct impacts of awards when calculating the amount of windfalls or shortfalls.
Stock-based compensation
We recognize stock-based compensation cost for only those shares ultimately expected to vest on a straight-line basis over the requisite service period of the award. We use the Black-Scholes option pricing model to determine the fair value of stock options and employee stock purchase plan shares. We estimate the fair value of market-performance based restricted stock units using a Monte Carlo simulation model which requires the input of assumptions, including expected term, stock price volatility and the risk-free rate of return.  In addition, judgment is also required in estimating the number of stock-based awards that are expected to be forfeited.  Forfeitures are estimated based on historical experience at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these estimates involve inherent uncertainties and the application of management’s judgment.  As a result, if factors change and we use different assumptions, our stock-based compensation expense could be materially different in the future.
Consolidation of Variable Interest Entities
For an entity in which we have variable interests, we focus on identifying which entity has the power to direct the activities that most significantly impact the variable interest entity’s economic performance and which enterprise has the obligation to absorb losses or the right to receive benefits from the variable interest entity. If we are the primary beneficiary of a variable interest entity, the assets, liabilities, and results of operations of the variable interest entity will be included in our Consolidated Financial Statements. For fiscal year 2014, 2013 and 2012, we did not have any material variable interest entities and did not consolidate any variable interest entities, because we are not a primary beneficiary.
Medical Device Excise Taxes
In accordance with the Patient Protection and Affordable Care Act, effective January 1, 2013, we began to incur an excise tax on sales of medical devices in the U.S. In March 2014, we were informed by IRS that our aligners are not subject to the medical device excise tax ("MDET") which we had been paying and expensing in general and administrative expenses in the consolidated statements of operations since January 1, 2013; however, our scanners are still subject to the MDET. Beginning in March 2014, we ceased expensing and paying the MDET for aligners. We are currently in process of claiming a $6.8 million refund of MDET paid in 2013 related to our aligners; however, because this claim is subject to review and approval by the IRS, we have not recorded a receivable as the outcome of the audit is uncertain. Any future changes in the applicability of the MDET as it applies to us or refunds of amounts previously paid will be recorded as an additional expense or a credit to the consolidated statement of operations in the period in which is becomes probable and reasonably estimable.
Comprehensive income
Comprehensive income includes all changes in equity during a period from non-owner sources. Comprehensive income, including unrealized gains and losses on available-for-sale securities and foreign currency translation adjustments, are reported net of their related tax effect.
Recent Accounting Pronouncements
In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09, “Revenue from Contracts with Customers,” requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. Early adoption is not permitted. The updated standard becomes effective for us in the first quarter of fiscal 2017. We have not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures.

Marketable_Securities_and_Fair

Marketable Securities and Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Marketable Securities and Fair Value Measurements	Marketable Securities and Fair Value Measurements
	As of December 31, 2014 and 2013, the estimated fair value of our short-term and long-term investments, classified as available for sale, are as follows (in thousands):
	Short-term
	31-Dec-14	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	Commercial paper	$	33,998		$	—		$	—		$	33,998
	Corporate bonds	152,055			27			(116		)	151,966
	U.S. dollar dominated foreign corporate bonds	901			—			—			901
	Municipal securities	9,147			13			—			9,160
	U.S. government agency bonds	41,574			14			(1		)	41,587
	U.S. government treasury bonds	15,770			7			—			15,777
	Certificates of Deposit	1,398			—			—			1,398
	Total Marketable Securities, Short-Term	$	254,843		$	61		$	(117	)	$	254,787
	Long-term
	31-Dec-14	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	U.S. government agency bonds	$	48,233		$	12		$	(28	)	$	48,217
	Corporate bonds	57,195			6			(112		)	57,089
	U.S. dollar dominated foreign corporate bonds	523			—			(2		)	521
	U.S. government treasury bonds	20,814			5			(6		)	20,813
	Municipal securities	9,552			5			(6		)	9,551
	Asset-backed securities	11,713			—			(12		)	11,701
	Total Marketable Securities, Long-Term	$	148,030		$	28		$	(166	)	$	147,892
	Short-term
	December 31, 2013	Amortized			Gross			Gross			Fair Value
		Cost			Unrealized			Unrealized
					Gains			Losses
	Commercial paper	$	54,318		$	10		$	—		$	54,328
	Corporate bonds	29,079			10			(4		)	29,085
	U.S. dollar dominated foreign corporate bonds	13,959			12			—			13,971
	Municipal securities	7,006			11			(3		)	7,014
	U.S. government agency bonds	16,693			10			—			16,703
	Asset-backed securities	5,937			2			—			5,939
	Total Marketable Securities, Short-Term	$	126,992		$	55		$	(7	)	$	127,040
	Long-term
	December 31, 2013	Amortized			Gross			Gross			Fair Value
		Cost			Unrealized			Unrealized
					Gains			Losses
	U.S. government agency bonds	$	38,138		$	1		$	(21	)	$	38,118
	Corporate bonds	23,308			14			(9		)	23,313
	U.S. dollar dominated foreign corporate bonds	19,485			27			(17		)	19,495
	U.S. government treasury bonds	6,916			3			—			6,919
	Municipal securities	8,326			13			(8		)	8,331
	Asset-backed securities	5,800			4			(2		)	5,802
	Total Marketable Securities, Long-Term	$	101,973		$	62		$	(57	)	$	101,978
	For the year ended December 31, 2014 and 2013, realized losses were immaterial. Cash and cash equivalents were not included in the table above as the gross unrealized gains and losses were not material. We have no material short-term or long-term investments that have been in continuous unrealized loss positions for greater than twelve months as of December 31, 2014. Amounts reclassified to earnings from unrealized gain or losses were immaterial in 2014 and 2013.
	Our fixed-income securities investment portfolio consists of corporate bonds, U.S. dollar dominated foreign corporate bonds, commercial paper, municipal securities, U.S. government agency bonds and asset-backed securities that have a maximum maturity of two years. 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 10 months and 11 months as of December 31, 2014 and 2013, 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 maturity as of December 31, 2014 and 2013  (in thousands):
			December 31,			December 31,
			2014			2013
	One year or less		$	254,787		$	127,040
	Due in greater than one year		147,892			101,978
	Total available for short-term and long-term marketable securities		$	402,679		$	229,018
	Fair Value Measurements
	We measure the fair value of our cash equivalents and marketable securities 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 U.S. 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.
	Our Level 1 assets consist of money market funds and U.S government treasury bonds. We did not hold any Level 1 liabilities as of December 31, 2014 or 2013.
	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.
	Our Level 2 assets consist of commercial paper, corporate bonds, U.S. dollar denominated foreign corporate bonds, municipal securities, U.S. government agency bonds, certificate of deposits, asset-backed securities, and our Israeli funds that are mainly invested in insurance policies. We obtain these fair values for level 2 investments from our asset manager for each of our portfolios. 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.
	We did not hold any Level 2 liabilities as of December 31, 2014 or 2013.
	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 ("DCF") methodologies or similar valuation techniques, as well as significant management judgment or estimation.
	We did not hold any Level 3 assets or liabilities as of December 31, 2014 or 2013.
Non-Recurring Fair Value Measurements
During 2013, we recorded an impairment charge to our long-lived assets and goodwill of $26.3 million and $40.7 million, respectively, related to our Scanner and Services ("Scanner") reporting unit as a triggering event occurred and circumstances changed that led us to perform an impairment analysis prior to our annual test which required us to determine the fair value of the Scanner reporting unit (Refer to Note 5). These fair value measurements were calculated using unobservable inputs, using the income approach which is classified as Level 3 within the fair value hierarchy. Inputs for the income approach includes the amount and timing of future cash flows based on our most recent operational budgets, strategic plans, terminal growth rates assumptions and other estimates.
The following tables summarizes our financial assets measured at fair value on a recurring basis as of December 31, 2014 and 2013 (in thousands):
Description	Balance as of			Quoted Prices in			Significant Other
	December 31, 2014			Active Markets for			Observable Inputs
				Identical Assets			(Level 2)
				(Level 1)
Cash equivalents:
Money market funds	$	80,786		$	80,786		$	—
Commercial paper	21,997			—			21,997
Corporate bonds	1,745			—			1,745
Short-term investments:
Commercial paper	33,998			—			33,998
Corporate bonds	151,966			—			151,966
U.S. dollar denominated foreign corporate bonds	901			—			901
Municipal securities	9,160			—			9,160
U.S. government agency bonds	41,587			—			41,587
U.S. government treasury bonds	15,777			15,777			—
Certificate of Deposits	1,398			—			1,398
Long-term investments:
Corporate bonds	57,089			—			57,089
U.S. government agency bonds	48,217			—			48,217
U.S. dollar denominated foreign corporate bonds	521			—			521
U.S. government treasury bonds	20,813			20,813			—
Municipal securities	9,551			—			9,551
Asset-backed securities	11,701			—			11,701
Long-term other assets:
Israeli funds	2,307			—			2,307
	$	509,514		$	117,376		$	392,138
Description	Balance as of			Quoted Prices in			Significant Other
	December 31, 2013			Active Markets for			Observable Inputs
				Identical Assets			(Level 2)
				(Level 1)
Cash equivalents:
Money market funds	$	143,540		$	143,540		$	—
Commercial paper	15,398			—			15,398
Short-term investments:
Commercial paper	54,328			—			54,328
Corporate bonds	29,085			—			29,085
U.S. dollar denominated foreign corporate bonds	13,971			—			13,971
Municipal securities	7,014			—			7,014
U.S. government agency bonds	16,703			—			16,703
Asset-backed securities	5,939			—			5,939
Long-term investments:
Corporate bonds	23,313			—			23,313
U.S. government agency bonds	38,118			—			38,118
U.S. dollar denominated foreign corporate bonds	19,495			—			19,495
U.S. government treasury bonds	6,919			6,919			—
Municipal securities	8,331			—			8,331
Asset-backed securities	5,802			—			5,802
Long-term other assets:
Israeli funds	2,193			—			2,193
	$	390,149		$	150,459		$	239,690

Balance_Sheet_Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Balance Sheet Components
	Inventories
	Inventories consist of the following (in thousands):
		December 31,
		2014				2013
	Raw materials	$	8,143			$	5,172
	Work in process	2,970				4,241
	Finished goods	4,815				4,555
	Total Inventories	$	15,928			$	13,968
	Work in process includes costs to produce our clear aligner and intra-oral scanner products. Finished goods primarily represent our intra-oral scanners and ancillary products that support our clear aligner products.
	Property, plant and equipment
	Property, plant and equipment consist of the following (in thousands):
			December 31,
			2014				2013
	Clinical and manufacturing equipment		$	107,707			$	104,373
	Computer hardware		24,092				24,851
	Computer software		22,044				21,286
	Furniture and fixtures		7,386				7,275
	Leasehold improvements		15,358				14,996
	Building		1,868				1,868
	Land		1,162				1,162
	CIP		18,310				5,438
	Total		197,927				181,249
	Less: Accumulated depreciation and amortization and impairment charges 1		(107,802		)		(105,506		)
	Total Property, plant and equipment, net		$	90,125			$	75,743
	1	We recorded an impairment of our long-lived assets in 2013 which was a result of changes in the competitive environment for intra-oral scanners which included announcements of new low-priced scanners targeted at orthodontists and GPs in North America that caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that the carrying value of the long-lived assets was not recoverable and therefore recorded an impairment charge of $26.3 million, of which $7.0 million related to property and equipment. Refer to Note 5 for details of the impairment analysis.
	As of December 31, 2014, CIP consists primarily of costs for capital equipment to be placed in service in the next year; however, in late 2014 we started an ERP project and have capitalized $2.6 million as of December 31, 2014, which we anticipate will be placed in service in 2016. Depreciation and amortization was $14.8 million, $13.9 million, and $13.4 million, for the year ended December 31, 2014, 2013 and 2012, respectively.
	Accrued liabilities
	Accrued liabilities consist of the following (in thousands):
		December 31,
		2014				2013
	Accrued payroll and benefits	$	44,610			$	43,029
	Accrued sales rebate	11,110				10,100
	Accrued sales and marketing expenses	5,979				3,893
	Accrued accounts payable	5,736				4,053
	Accrued sales tax and value added tax	5,456				6,215
	Accrued warranty	3,148				3,104
	Accrued professional fees	2,494				1,892
	Accrued income taxes	2,027				1,205
	Other accrued liabilities	7,320				6,854
	Total Accrued Liabilities	$	87,880			$	80,345
	Warranty
	We regularly review the accrued balances and update these balances 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.
	Clear Aligner
	We warrant our Invisalign products against material defects until the Invisalign case is complete. We accrue for warranty costs in cost of net revenues upon shipment of products. The amount of accrued estimated warranty costs is primarily based on historical experience as to product failures as well as current information on replacement costs.
	Scanners
	We warrant our scanners for a period of one year from the date of training and installation. We accrue for these warranty costs which includes materials and labor based on estimated historical repair costs. Extended service packages may be purchased for additional fees.
	Warranty accrual as of December 31, 2014 and 2013 consists of the following activity (in thousands):
	Warranty accrual, December 31, 2012	$	4,050
	Charged to cost of revenues	2,850
	Actual warranty expenditures	(3,796		)
	Warranty accrual, December 31, 2013	3,104
	Charged to cost of revenues	1,990
	Actual warranty expenditures	(1,946		)
	Warranty accrual, December 31, 2014	$	3,148

Business_Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Business Combinations	Business Combinations
	Cadent
	On April 29, 2011, we completed the acquisition of Cadent, a 3D digital scanning solution for orthodontics and dentistry, for an aggregate cash purchase price of approximately $187.6 million . We recorded goodwill of $135.3 million as a result of the acquisition, which represents the excess of the purchase price over the fair value of the underlying net tangible and identifiable intangible assets, and represents the expected synergies of the transaction and the knowledge and experience of the workforce in place. None of the goodwill is deductible for tax purposes. In connection with the acquisition, we allocated approximately $77.3 million of the goodwill from the Cadent acquisition to our Scanner and Services ("Scanner") reporting unit and approximately $58.0 million to our Clear Aligner reporting unit based on the expected relative synergies generated by the acquisition. During the third quarter of 2012, we determined that goodwill for our Scanner reporting unit should be tested for impairment between annual impairment tests since an event occurred or circumstances changed that would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. We recorded a total impairment charge of $36.6 million for the Scanner for 2012 after finalizing step two of our analysis.  Further, during March 2013, changes in the competitive environment for intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists in North America, caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that goodwill related only to our Scanner reporting unit should be tested for impairment as of March 2013 due to these facts and circumstances which would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. Based on our analysis, there was no implied goodwill for the Scanner reporting unit; therefore, we recorded a goodwill impairment charge of $40.7 million in the three months ended March 31, 2013, which represents the remaining goodwill balance in the Scanner reporting unit. All remaining goodwill from the Cadent acquisition as of December 31, 2014 is attributable to the Clear Aligner segment. See Note 5 for discussion of our goodwill impairment.
	ICA Holdings Pty Limited
	On April 30, 2013, we completed the acquisition of ICA Holdings Pty Limited ("ICA") upon the expiration of the distribution agreement between certain subsidiaries of ICA and Align Technology B.V., for a total cash consideration of approximately $8.6 million, of which $7.4 million was attributed to assets acquired, $2.4 million in liabilities assumed and $3.6 million to goodwill. Goodwill as a result of this acquisition represents the excess of the purchase price over the fair value of the underlying net assets acquired and represents the knowledge and experience of the workforce in place. None of this goodwill will be deductible for tax purposes. Under the applicable accounting guidance, goodwill will not be amortized but will be tested for impairment on an annual basis or more frequently if certain indicators are present.
	Pro forma results of operations for this acquisition have not been presented as it is not material to our results of operations, either individually or in aggregate, for the year ended 2013.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets
	Goodwill
	The change in the carrying value of goodwill for the year ended December 31, 2014 by our reportable segments, which are also our reporting units, are as follows (in thousands):
		Clear Aligner				Scanners and				Total
						Services
	Balance as of December 31, 2012	$	58,543			$	40,693			$	99,236
	Goodwill from ICA acquisition	3,558				—				3,558
	Impairment of goodwill	—				(40,693		)		(40,693		)
	Adjustments 1	(478		)		—				(478		)
	Balance as of December 31, 2013	61,623				—				61,623
	Goodwill from ICA acquisition	—				—				—
	Adjustments 1	(254		)		—				(254		)
	Balance as of December 31, 2014	$	61,369			$	—			$	61,369
	1	The adjustments to goodwill were a result of foreign currency translation.
	Impairment of Goodwill
	We evaluate goodwill for impairment at least annually on November 30th or more frequently if indicators are present, an event occurs or circumstances changes that suggest an impairment may exist and that it would more likely than not reduce the fair value of a reporting unit below its carrying amount.  The allocation of goodwill to the respective reporting unit is based on relative synergies generated as a result of an acquisition.
	2012 Impairment
	During the third quarter of 2012, we determined that the goodwill for our Scanner reporting unit should be tested for impairment between annual impairment tests since an event occurred/circumstances changed that would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. These indicators included the termination of an exclusive distribution arrangement with Straumann for iTero intra-oral scanners in Europe, as well as the termination of their non-exclusive distribution arrangement for iTero intra-oral scanners in North America, together with market conditions and business trends within the Scanner reporting unit. While we continued to expect revenue growth in our Scanner business, our expectations for future growth and profitability rates projected for the Scanner reporting unit were lower than our previous estimates primarily driven by overall lower than expected financial results.
	As a result, we performed step one analysis for our Scanner reporting unit, which consists of a comparison of the fair value of the Scanner reporting unit against its carrying amount, including the goodwill allocated to it. In deriving the fair value of the Scanner reporting unit, we utilized a combination of both the income and market approach, which are classified as level 3 within the fair value hierarchy. The income approach provides an estimate of fair value based on discounted expected future cash flows. The market approach provides an estimate of fair value using various prices or market multiples applied to the reporting unit's operating results and then applies an appropriate control premium in order to reconcile to our market capitalization. As a result of our step one analysis, we concluded that the fair value of the Scanner reporting unit was less than its carrying value, therefore, we proceeded to perform step two of the goodwill impairment analysis.
	Step two of the goodwill impairment analysis measures the impairment charge by allocating the reporting unit's fair value to all of the assets and liabilities of the reporting unit in a hypothetical analysis that calculates the implied fair value of goodwill in the same manner as if the reporting unit was being acquired in a business combination. This allocation process was performed only for the purposes of measuring the goodwill impairment, and not to adjust the carrying values of the recognized tangible assets and liabilities. Any excess of the carrying value of the reporting unit's goodwill over the implied fair value of the reporting unit's goodwill is recorded as an impairment loss. Based on our analysis, the implied fair value of goodwill was substantially lower than the carrying value of the goodwill for the Scanner reporting unit. We recorded a preliminary goodwill impairment charge during the third quarter of 2012 of $24.7 million and an additional $11.9 million during the fourth quarter of 2012, representing a change in estimate upon finalizing our 2013 annual budget process, for a total impairment charge of $36.6 million. None of the goodwill impairment charge was deductible for tax purposes.
	2013 Impairment
	During March 2013, changes in the competitive environment for intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists in North America, caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that goodwill related only to our Scanner reporting unit should be tested for impairment as of March 2013 due to these facts and circumstances which would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. There was no triggering event related to the Clear Aligner goodwill.
	We performed a step one analysis for our Scanner reporting unit which consists of a comparison of the fair value of the Scanner reporting unit against its carrying amount, including the goodwill allocated to it. In deriving the fair value of the Scanner reporting unit, we utilized the income approach which is classified as Level 3 within the fair value hierarchy. This approach provides an estimated fair value based on discounted expected future cash flows, which are based on management's estimates of revenue growth rates and operating margins, taking into consideration industry and market conditions. The discount rate used is based on a weighted average cost of capital adjusted for the relevant risk associated with the characteristics of the business and the projected cash flows.
	As a result of our step one analysis, we concluded that the fair value of the Scanner reporting unit was less than its carrying value; therefore, we proceeded to step two of the goodwill impairment analysis. Step two of the goodwill impairment analysis measures the impairment charge by allocating the reporting unit's fair value to all of the assets and liabilities of the reporting unit in a hypothetical analysis that calculates the implied fair value of goodwill in the same manner as if the reporting unit was being acquired in a business combination. This allocation process was performed only for the purposes of measuring the goodwill impairment and not to adjust the carrying values of the recognized tangible assets and liabilities. Any excess of the carrying value of the reporting unit's goodwill over the implied fair value of the reporting unit's goodwill is recorded as an impairment loss. We use a discounted cash flow (“DCF”) approach to estimate the fair value of a reporting unit, utilizing the harvest model, which we believe is the most reliable indicator of fair value of this business, and is most consistent with the approach a market place participant would use. Based on our analysis, there was no implied goodwill for the Scanner reporting unit; therefore, we recorded a goodwill impairment charge of $40.7 million in the three months ended March 31, 2013, which represents the remaining goodwill balance in the Scanner reporting unit. None of the goodwill impairment charge was deductible for tax purposes.
	Annual Impairment Test
	The remaining goodwill is entirely attributable to our Clear Aligner reporting unit. During the fourth quarter of fiscal 2014, we performed the annual goodwill impairment testing and found no impairment events as the fair value of our Clear Aligner reporting unit was significantly in excess of the carrying value.
	Acquired Intangible Assets
	We amortize our intangible assets over their estimated useful lives. We evaluate long-lived assets, which includes property, plant and equipment and intangible assets, for impairment whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The carrying value is not recoverable if it exceeds the undiscounted cash flows resulting from the use of the asset and its eventual disposition. Our estimates of future cash flows attributable to our long-lived assets require significant judgment based on our historical and anticipated results and are subject to many factors. Factors we consider important which could trigger an impairment review include significant negative industry or economic trends, significant loss of customers and changes in the competitive environment of our intra-oral scanning business.
	During March 2013, changes in the competitive environment for intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists in North America, that caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that the carrying value of the Scanner long-lived assets was not recoverable as compared to the value of the undiscounted cash flows of our revised projections for the asset group. In order to determine the impairment amount of our long-lived assets, we fair valued each key component of our long-lived assets within the asset group, which involved the use of significant estimates and assumptions including replacement costs, revenue growth rates, operating margins, and plant and equipment cost trends. We use a DCF approach, utilizing the harvest model, to estimate the fair value of a reporting unit, which we believe is the most reliable indicator of fair value of a business, and is most consistent with the approach of a marketplace participant would use. The estimation of fair value utilizing a DCF approach includes numerous uncertainties which require our significant judgment when making assumptions of expected growth rates and the selection of discount rates, as well as assumptions regarding general economic and business conditions, and the structure that would yield the highest economic value, among other factors. Key assumptions used in measuring the fair values of Scanner reporting unit included the discount rate (based on the weighted-average cost of capital) and revenue growth. The fair value of Scanner’s trademark was determined using a risk-adjusted DCF approach under the relief-from-royalty method. The royalty rate used was based on a consideration of market rates. The fair value of Scanner’s finite-lived customer relationships was determined using a DCF approach under the multi-period excess earnings method. We determined our long-lived asset group within the Scanner reporting unit to be primarily finite-lived intangible assets, plant and equipment. Upon completion of this analysis, we recorded a total impairment charge of $26.3 million of which $19.3 million represented the impairment related to our Scanner intangible assets and $7.0 million related to plant and equipment. There was no triggering event related to the Clear Aligner asset group.
	There were no triggering events in 2014 that would cause further impairments of our long-lived assets.
	Intangible assets arising either as a direct result from the Cadent acquisition or individually acquired are being amortized as follows (in thousands):
		Weighted Average Amortization Period (in years)		Gross Carrying Amount as of				Accumulated				Impairment Charge			Net Carrying
				December 31, 2014				Amortization							Value as of
															31-Dec-14
	Trademarks	15		$	7,100			$	(1,354	)		$	(4,179	)	$	1,567
	Existing technology	13		12,600				(3,015		)		(4,328		)	5,257
	Customer relationships	11		33,500				(9,095		)		(10,751		)	13,654
	Other	8		285				(76		)		—			209
	Total Intangible Assets			$	53,485			$	(13,540	)		$	(19,258	)	$	20,687
		Weighted Average Amortization Period (in years)		Gross Carrying				Accumulated				Impairment Charge			Net Carrying
				Amount as of				Amortization							Value as of
				31-Dec-13											31-Dec-13
	Trademarks	15		$	7,100			$	(1,100	)		$	(4,179	)	$	1,821
	Existing technology	13		12,600				(2,236		)		(4,328		)	6,036
	Customer relationships	11		33,500				(7,112		)		(10,751		)	15,637
	Other	8		285				(40		)		—			245
	Total Intangible Assets			$	53,485			$	(10,488	)		$	(19,258	)	$	23,739
	The total estimated annual future amortization expense for these acquired intangible assets as of December 31, 2014 is as follows (in thousands):
	Fiscal Year
	2015	$	2,600
	2016	2,600
	2017	2,600
	2018	2,600
	2019	2,600
	Thereafter	7,687
	Total	$	20,687

Legal_Proceedings

Legal Proceedings	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal Proceedings
	Securities Class Action Lawsuit
	On November 28, 2012, plaintiff City of Dearborn Heights Act 345 Police & Fire Retirement System filed a lawsuit against Align, Thomas M. Prescott (“Mr. Prescott”), Align’s President and Chief Executive Officer, and Kenneth B. Arola (“Mr. Arola”), Align’s former Vice President, Finance and Chief Financial Officer, in the United States District Court for the Northern District of California on behalf of a purported class of purchasers of our common stock (the “Securities Action”). On July 11, 2013, an amended complaint was filed, which named the same defendants, on behalf of a purported class of purchasers of our common stock between January 31, 2012 and October 17, 2012. The amended complaint alleged that Align, Mr. Prescott and Mr. Arola violated Section 10(b) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder, and that Mr. Prescott and Mr. Arola violated Section 20(a) of the Securities Exchange Act of 1934. Specifically, the amended complaint alleged that during the purported class period defendants failed to take an appropriate goodwill impairment charge related to the April 29, 2011 acquisition of Cadent Holdings, Inc. in the fourth quarter of 2011, the first quarter of 2012 or the second quarter of 2012, which rendered our financial statements and projections of future earnings materially false and misleading and in violation of U.S. GAAP. The amended complaint sought monetary damages in an unspecified amount, costs and attorneys’ fees. On December 9, 2013, the court granted defendants’ motion to dismiss with leave for plaintiff to file a second amended complaint. Plaintiff filed a second amended complaint on January 8, 2014 on behalf of the same purported class. The second amended complaint states the same claims as the amended complaint. On August 22, 2014, the court granted our motion to dismiss without leave to amend. On September 22, 2014, Plaintiff filed a notice of appeal to the Ninth Circuit Court of Appeals. Align intends to vigorously defend itself against these allegations. Align is currently unable to predict the outcome of this amended complaint and therefore cannot determine the likelihood of loss nor estimate a range of possible loss, if any.
	Shareholder Derivative Lawsuit
	On February 1, 2013, plaintiff Gary Udis filed a shareholder derivative lawsuit against several of Align’s current and former officers and directors in the Superior Court of California, County of Santa Clara. The complaint alleges that our reported income and earnings were materially overstated because of a failure to timely write down goodwill related to the April 29, 2011 acquisition of Cadent Holdings, Inc., and that defendants made allegedly false statements concerning our forecasts. The complaint asserts various state law causes of action, including claims of breach of fiduciary duty, unjust enrichment, and insider trading, among others. The complaint seeks unspecified damages on behalf of Align, which is named solely as nominal defendant against whom no recovery is sought. The complaint also seeks an order directing Align to reform and improve its corporate governance and internal procedures, and seeks restitution in an unspecified amount, costs, and attorneys’ fees. On July 8, 2013, an Order was entered staying this derivative lawsuit until an initial ruling on our first motion to dismiss the Securities Action. On January 15, 2014, an Order was entered staying this derivative lawsuit until an initial ruling on our second motion to dismiss the Securities Action. On October 14, 2014, an Order was entered staying this derivative lawsuit until a ruling by the Ninth Circuit in the Securities Action discussed above. Align is currently unable to predict the outcome of this complaint and therefore cannot determine the likelihood of loss nor estimate a range of possible losses.
	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.

Credit_Facilities

Credit Facilities	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Credit Facilities	Credit Facilities
	On March 22, 2013, we entered into a credit facility with Wells Fargo Bank. The credit facility provides for a $50.0 million revolving line of credit, with a $10.0 million letter of credit sublimit, and has a maturity date on March 22, 2016. The credit facility also requires us to maintain a minimum unrestricted cash balance of $50.0 million and comply with specific financial conditions and performance requirements. The loans bear interest, at our option, at a fluctuating rate per annum equal to the daily one-month adjusted LIBOR rate plus a spread of 1.75% or an adjusted LIBOR rate (based on one, three, six or twelve-month interest periods) plus a spread of 1.75%. As of December 31, 2014, we had no outstanding borrowings under this credit facility and were in compliance with the conditions and performance requirements.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Operating leases
	We lease our facilities and certain equipment and automobiles under non-cancelable operating lease arrangements that expire at various dates through 2022 and provide for pre-negotiated fixed rental rates during the terms of the lease. The terms of some of our leases provide for rental payments on a graduated scale. We recognize rent expense on a straight-line basis over the lease period and accrue for any rent expense incurred but not paid. Total rent expense was $7.6 million, $7.3 million and $6.9 million, for the year ended December 31, 2014, 2013 and 2012, respectively.
	Minimum future lease payments for non-cancelable leases as of December 31, 2014, are as follows (in thousands):
	Fiscal Year	Operating leases
	2015	$	9,130
	2016	8,293
	2017	4,659
	2018	1,545
	2019	209
	Thereafter	210
	Total minimum lease payments	$	24,046
	Off-balance Sheet Arrangements
	As of December 31, 2014, we had no 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.
	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 certain of our 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 December 31, 2014, we did not have any material indemnification claims that were probable or reasonably possible.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity
	Preferred Stock Rights Agreement
	The Preferred Stock Rights Agreement (the “Rights Agreement”) is intended to protect stockholders from unfair or coercive takeover practices.  In accordance with the Rights Agreement, the Board of Directors declared a dividend distribution of one preferred stock purchase right (a “Right”) for each outstanding share of our common stock to stockholders of record on November 22, 2005. Each Right entitles stockholders to buy one one-thousandth of a share of our Series A Participating Preferred Stock, par value $0.0001 per share, at an exercise price of $37.00, subject to adjustment. Rights will become exercisable upon the occurrence of certain events, including a person or group acquiring or the announcing the intention to acquire beneficial ownership of 15% or more of the then outstanding common stock without the approval of the Board of Directors. Each holder of a Right will have the right to receive, upon exercise, shares of common stock having a value equal to two times the purchase price. The Rights will expire on November 22, 2015 or upon the exercise of the Rights, whichever occurs earlier.
	Common Stock
	The holders of common stock are entitled to receive dividends whenever funds are legally available and when and if declared by the Board of Directors. We have never declared or paid dividends on our common stock.
	Stock-based Compensation Plans
	Our 2005 Incentive Plan, as amended, provides for the granting of incentive stock options, non-statutory stock options, restricted stock units, market stock units, stock appreciation rights, performance units and performance shares to employees, non-employee directors, and consultants. Shares granted on or after May 16, 2013 as an award of restricted stock, restricted stock unit, market stock units, performance share or performance unit ("full value awards") are counted against the authorized share reserve as one and nine-tenths (1 9/10) shares for every one (1) share subject to the award, and any shares canceled that were counted as one and nine-tenths against the plan reserve will be returned at the same ratio. Full value awards granted prior to May 16, 2013 were counted against the authorized share reserve as one and one half (1 1/2) share for every one (1) share subject to the award, and any shares canceled that were counted as one and one half against the plan reserve will be returned at this same ratio.
	As of December 31, 2014, the 2005 Incentive Plan (as amended) has a total reserve of 23,283,379 shares for issuance of which 7,325,130 shares are available for issuance, plus up to an aggregate of 5,000,000 shares that would have been returned to our 2001 Stock Incentive Plan as a result of termination of options on or after March 28, 2005. No shares were added to the plan in 2014. We issue new shares from our pool of authorized but unissued shares to satisfy the exercise and vesting obligations of our stock-based compensation plans.
	Stock-based Compensation
	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 year ended December 31, 2014, 2013 and 2012 is as follows (in thousands):
		For the Year Ended December 31,
		2014				2013				2012
	Cost of net revenues	$	3,616			$	2,565			$	1,843
	Sales and marketing	11,646				7,093				5,581
	General and administrative	17,979				13,261				10,361
	Research and development	6,582				3,519				3,698
	Total stock-based compensation	$	39,823			$	26,438			$	21,483
	Stock Options
	Options are granted for terms not to exceed seven years and generally vest over four years with 25% vesting one year from the date of grant and 1/48th each month thereafter.  Activity for the year ended December 31, 2014, under the stock option plans are set forth below (in thousands, except years and per share amounts):
		Stock Options
		Number of			Weighted				Weighted Average		Aggregate
		Shares			Average				Remaining		Intrinsic
		Underlying			Exercise				Contractual Term		Value
		Stock Options			Price per Share				(in years )
	Outstanding as of December 31, 2013	1,321			16.08
	Granted	—			—
	Exercised	(648	)		16.58
	Cancelled or expired	(5	)		18.32
	Outstanding as of December 31, 2014	668			$	15.57			2.92		$	26,933
	Vested and expected to vest at December 31, 2014	668			$	15.57			2.92		$	26,930
	Exercisable at December 31, 2014	655			$	15.43			2.92		$	26,504
	The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between our closing stock price on the last trading day in 2014 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on December 31, 2014.  This amount will fluctuate based on the fair market value of our stock.  The total intrinsic value of stock options exercised for the year ended December 31, 2014, 2013 and 2012 was $24.5 million, $46.7 million and $50.9 million, respectively.  The total fair value of the options vested during the year ended December 31, 2014, 2013 and 2012 was $0.7 million, $3.7 million, $5.0 million, respectively.  There were no stock options granted in 2014, 2013 and 2012.
	As of December 31, 2014, the total unamortized compensation costs related to stock options was not material. For the year ended December 31, 2014, the total recognized tax effect from exercised options was $1.9 million.
	Restricted Stock Units
	The fair value of nonvested restricted stock units (“RSUs”) is based on our closing stock price on the date of grant.  A summary for the year ended December 31, 2014, is as follows (in thousands, except years and per share amounts):
		Shares			Weighted Average Grant Date Fair Value				Weighted		Aggregate
		Underlying  RSUs							Remaining		Intrinsic
									Vesting Period		Value
									(in years)
	Nonvested as of December 31, 2013	2,044			$	31.88
	Granted	981			53.72
	Vested and released	(728	)		30.22
	Forfeited	(173	)		37.59
	Nonvested as of December 31, 2014	2,124			$	42.08			1.33		$	118,727
	The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (calculated by multiplying our closing stock price on the last trading day of 2014 by the number of nonvested RSUs) that would have been received by the unit holders had all RSUs been vested and released on December 31, 2014. This amount will fluctuate based on the fair market value of our stock.  During 2014, of the 727,679 shares vested and released, 114,468 vested shares were withheld for employee minimum statutory tax obligations, resulting in a net issuance of 613,211 shares.
	The total intrinsic value of RSUs vested and released during 2014, 2013 and 2012 was $38.9 million, $20.3 million and $12.5 million, respectively. The total fair value RSUs vested during the year ended December 31, 2014, 2013, and 2012 was $22.0 million, $13.2 million, $7.8 million, respectively. As of December 31, 2014, there was $32.1 million of total unamortized compensation costs, net of estimated forfeitures, related to RSUs, and these costs are expected to be recognized over a weighted average period of 2.2 years.
	On an annual basis, we grant market-performance based restricted stock units (“MSUs”) to our executive officers. Each MSU represents the right to one share of Align’s common stock and will be issued through our amended 2005 Incentive Plan. 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 the NASDAQ Composite Index over the vesting period, generally two to three years, up to 150% of the MSUs initially granted.
	The following table summarizes the MSU performance as of December 31, 2014:
		Number of  Shares			Weighted Average Grant Date Fair Value			Weighted  Average		Aggregate
		Underlying MSUs						Remaining		Intrinsic  Value
		(in thousands)						Vesting Period		(in thousands)
								(in years )
	Nonvested as of December 31, 2013	307			31.96
	Granted	244			50.46
	Vested and released	(53	)		22.41
	Nonvested as of December 31, 2014	498			42			1.38		$	27,815
	The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (calculated by multiplying our closing stock price on the last trading day of 2014 by the number of non-vested MSUs) that would have been received by the unit holders had all MSUs been vested and released on December 31, 2014. This amount will fluctuate based on the fair market value of our stock.  During 2014, of the 52,575 shares vested and released 25,214 shares were withheld for tax payments, resulting in a net issuance of 27,361 shares.
	The total intrinsic value of MSUs vested and released during 2014 was $2.9 million. The total fair value MSUs vested during the year ended December 31, 2014 was $1.2 million. As of December 31, 2014, we expect to recognize $6.2 million of total unamortized compensation cost, net of estimated forfeitures, related to MSUs over a weighted average period of 1.4 years.
	The fair value of the MSUs is estimated at the grant date using a Monte Carlo simulation that includes factors for market conditions.  The following weighted-average assumptions used in the Monte Carlo simulation were as follows:
		Year Ended December 31,
		2014				2013				2012
	Expected term (in years)	3				3				3
	Expected volatility	46		%		47		%		54		%
	Risk-free interest rate	0.7		%		0.4		%		0.4		%
Expected dividends	—				—				—
Weighted average fair value per share at grant date	$	50.46			$	35.49			$	29.45
Total payments to tax authorities for payroll taxes related to RSUs, including MSUs, that vested during the period, were $7.6 million, $4.4 million and $2.1 million in 2014, 2013 and 2012, respectively, reflected as a financing activity in the Consolidated Statements of Cash Flows.
Employee Stock Purchase Plan
In May 2010, our shareholders approved the 2010 Employee Stock Purchase Plan (the “2010 Purchase Plan”), replacing our 2001 Employee Stock Purchase Plan, which consists of consecutive overlapping twenty-four month offering periods with four six-month purchase periods in each offering period. Employees purchase shares at 85% of the fair market value of the common stock at either the beginning of the offering period or the end of the purchase period, whichever is lower. The 2010 Purchase Plan will continue until terminated by either the Board or its administrator.  The maximum number of shares available for issuance under the 2010 Purchase Plan is 2,400,000 shares. During the year ended December 31, 2014, 2013 and 2012, we issued 247,343, 288,675, and 336,382 shares, respectively, at average prices of $29.24, $21.96 and $17.98, respectively. As of December 31, 2014, 1,363,827 shares remain available for future issuance.
The fair value of the option component of the Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
	Year Ended December 31,
	2014				2013				2012
Employee Stock Purchase Plan:
Expected term (in years)	1.2				1.2				1.2
Expected volatility	38.8		%		44.9		%		49.7		%
Risk-free interest rate	0.2		%		0.2		%		0.2		%
Expected dividends	—				—				—
Weighted average fair value at grant date	$	17.15			$	11.69			$	11.1
We recognized stock-based compensation expense of $2.6 million, $3.4 million, $2.0 million related to our employee stock purchase plans for the year ended December 31, 2014, 2013 and 2012, respectively. As of December 31, 2014, there was $0.8 million of total unamortized compensation costs related to employee stock purchases. These costs are expected to be recognized over a weighted average period of 0.3 years.

Common_Stock_Repurchase_Progra

Common Stock Repurchase Program	12 Months Ended
	Dec. 31, 2014
Notes To Financial Statements [Abstract]
Share Repurchase Program Disclosure [Text Block]	Common Stock Repurchase Program
	On October 27, 2011, we announced that our Board of Directors approved a stock repurchase program pursuant to which we may repurchase up to $150.0 million of common stock.  Purchases under the stock repurchase program were made from time to time in the open market.
	During 2012, we repurchased approximately 1.7 million shares of common stock at an average price of $27.28 per share for an aggregate purchase price of approximately $47.2 million, including commissions.  The common stock repurchases reduced additional paid-in capital by approximately $15.4 million and increased accumulated deficit by $31.8 million.  During 2013, we repurchased approximately 2.7 million shares of our common stock at an average price of $34.95 per share, including commissions, for an aggregate purchase price of approximately $95.1 million. The common stock retirements reduced additional paid-in capital by approximately $24.5 million and increased accumulated deficit by $70.6 million.  All repurchased shares were retired.  No further authorization for repurchases remains outstanding as we completed the repurchases under this program as of December 31, 2013.
	On April 23, 2014, we announced that our Board of Directors had authorized a stock repurchase program pursuant to which we may purchase up to $300.0 million of our common stock over the next three years, with $100.0 million of that amount authorized to be purchased over the first twelve months. Any purchases under this stock repurchase program may be made, from time-to-time, pursuant to open market purchases (including pursuant to Rule 10b5-1 plans), privately-negotiated transactions, accelerated stock repurchases, block trades or derivative contracts or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934.
	As part of our $300.0 million stock repurchase program, we entered into an accelerated share repurchase agreement ("ASR") with Goldman, Sachs & Co. on April 28, 2014 to repurchase $70.0 million of our common stock. We paid $70.0 million on April 29, 2014 and received an initial delivery of approximately 1.0 million shares. The ASR was completed on July 29, 2014 with a final delivery of approximately 0.4 million shares. We received a total of approximately 1.4 million shares under the ASR for an average purchase price per share of $51.46, which all shares were retired. The final number of shares repurchased was based on our volume-weighted average stock price during the term of the transaction, less an agreed upon discount.
	During 2014, we repurchased on the open market approximately 0.6 million shares of our common stock at an average price of $50.93 per share, including commissions, for an aggregate purchase price of approximately $28.2 million. All repurchased shares were retired. As of December 31, 2014, we have $201.8 million remaining under the April 2014 stock repurchase program, of which $1.8 million was repurchased in January 2015. In addition, in January 2015, our Board of Directors has authorized the next $100.0 million under the program to be repurchased which we anticipate completing within twelve months. We expect to finance future stock repurchases with current cash on hand.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation Related Costs [Abstract]
Employee Benefit Plans	Employee Benefit Plans
	401(k) Plan
	In January 1999, we adopted a defined contribution retirement plan under Section 401(k) of the Internal Revenue Code for our U.S. employees. This plan covers substantially all U.S. employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. In 2009, our Board of Directors authorized us to match 50% of our employee’s salary deferral contributions up to a 6% of the employee’s eligible compensation effective 2010. We contributed approximately $2.2 million, $2.1 million and $1.9 million to the 401(k) plan during 2014, 2013 and 2012, respectively.
	Israeli Funds
	Under the Israeli severance fund law, we are required to make payments to dismissed employees and employees leaving employment in certain circumstances. The funding is calculated based on the salary of the employee multiplied by the number of years of employment as of the applicable balance sheet date. Our Israeli employees are entitled to one month’s salary for each year of employment, or a pro-rata portion thereof.  We fund the liability through monthly deposits into funds, and the values of these contributions are recorded in other long-term current assets.
	As of December 31, 2014 and 2013, the accrued funds liability was approximately $2.5 million and $2.4 million, respectively.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	Income before provision for income taxes consisted of the following (in thousands):
		Year ended December 31,
		2014				2013				2012
	Domestic	$	94,784			$	31,993			$	32,341
	Foreign	95,585				61,146				51,955
	Total Income before provision for income taxes	$	190,369			$	93,139			$	84,296
	The provision for income taxes consisted of the following (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Federal
	Current	$	1,569			$	26			$	—
	Deferred	37,570				24,262				22,382
		39,139				24,288				22,382
	State
	Current	2,162				1,235				438
	Deferred	971				1,158				1,486
		3,133				2,393				1,924
	Foreign
	Current	1,596				3,113				1,173
	Deferred	669				(950		)		126
		2,265				2,163				1,299
	Provision for income taxes	$	44,537			$	28,844			$	25,605
	The differences between income taxes using the federal statutory income tax rate of 35% and our effective tax rate were as follows:
		Year Ended December 31,
		2014			2013			2012
	U.S. federal statutory income tax rate	35	%		35	%		35	%
	State income taxes, net of federal tax benefit	1.6			2.5			2.4
	Impact of differences in foreign tax rates	(16.4	)		(20.4	)		(20.0	)
	Goodwill Impairment	—			15.3			15.2
	Stock-based compensation	1			0.5			(1.2	)
	Other items not individually material	2.2			(1.9	)		(1.0	)
		23.4	%		31	%		30.4	%
	Other items not individually material for the year ended December 31, 2014 includes an out of period correction that resulted in an increase in the provision for income taxes of $1.8 million. We do not believe the out of period adjustment is material to the consolidated financial statements for the fiscal year ended December 31, 2014 or to any prior years' consolidated financial statements.
	As of December 31, 2014, U.S. income taxes and foreign withholding taxes associated with the repatriation of undistributed earnings of foreign subsidiaries were not provided for on a cumulative total of $260.9 million. We intend to reinvest these earnings indefinitely in our foreign subsidiaries. If these earnings were distributed in the form of dividends or otherwise, or if the shares of the relevant foreign subsidiaries were sold or otherwise transferred, we would be subject to additional U.S. income taxes and foreign withholding taxes, net of related foreign tax credits. Determination of the amount of unrecognized deferred income tax liability related to these earnings is not practicable.
	In June 2009, the Costa Rica Ministry of Foreign Trade, an agency of the Government of Costa Rica, granted a twelve year extension of certain tax incentives, which were previously granted in 2002. The incentive tax rates will expire in various years beginning in 2017. Under these incentives, all of the income in Costa Rica during these twelve year incentive periods is subject to reduced rates of Costa Rica income tax. In order to receive the benefit of the incentives, we must hire specified numbers of employees and maintain 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 2014. As a result of these incentives, income taxes were reduced by $32.5 million, $27.7 million, and $21.8 million in 2014, 2013, and 2012, respectively. The benefit of the tax holiday on diluted net income per share was $0.40, $0.34, and $0.26 in 2014, 2013 and 2012, respectively.
	As of December 31, 2014 and 2013, the significant components of our deferred tax assets and liabilities were (in thousands):
		Year Ended December 31,
		2014				2013
	Deferred tax assets:
	Net operating loss and capital loss carryforwards	$	33,202			$	39,978
	Credit carryforwards	1,446				9,362
	Reserves and accruals	32,888				26,729
	Translation gains	637				48
	Stock-based compensation	11,964				9,100
		80,137				85,217
	Deferred tax liabilities:
	Prepaid expenses	709				557
	Depreciation and amortization	6,878				5,320
		7,587				5,877
	Net deferred tax assets before valuation allowance	72,550				79,340
	Valuation allowance	(32,498		)		(35,108		)
	Net deferred tax assets	$	40,052			$	44,232
	We assess the likelihood that we will be able to realize our deferred tax assets quarterly. We consider all available evidence, both positive and negative, including historical levels of income, expectations and risks associated with estimates of future taxable income and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. If it is more likely than not that we do not expect to realize our deferred tax assets, we will increase our provision for income taxes by recording a valuation allowance against the deferred tax assets that we estimate will not ultimately be realizable. As of December 31, 2014, we believed, except for the items noted in the subsequent paragraph, that it was more likely than not that the amount of deferred tax assets recorded on the balance sheet will be realized.
	The $32.5 million total valuation allowance provided against our deferred tax assets at December 31, 2014, relates primarily to foreign net operating loss and capital loss carryforwards. At December 31, 2014, the valuation allowance decreased by a net $2.6 million, due to a $1.8 million decrease related to foreign net operating loss carryforwards, and a decrease of $0.8 million due to the release of valuation allowance related to Japan and China deferred tax assets.
	At December 31, 2014, we had fully utilized net operating loss carryforwards for federal purposes and have net operating loss carryforwards of $37.3 million for California state tax purposes. If not utilized, these carryforwards will begin to expire in 2015 for California purposes.  In addition, we had foreign net operating loss carryforwards of approximately $125.5 million, which, if not utilized will expire beginning in 2017.
	Our net operating loss carryforwards associated with the exercise of employee stock options totaled $23.8 million as of December 31, 2014 for California state tax purposes, which was not included in our deferred tax assets. The reduction of income taxes payable by the tax benefits associated with the exercise of employee stock options during the fiscal year, and utilization of net operating loss carryover applicable to stock options were approximately $21.4 million, $27.1 million, and $17.2 million in 2014, 2013, and 2012, respectively. The benefits applicable to stock options were credited directly to stockholders’ equity when realized. We follow the tax law ordering method to determine when excess tax benefits have been realized and consider only the direct impacts of awards when calculating the amount of windfalls or shortfalls.
	At December 31, 2014, we have California research credit carryforwards of approximately $3.8 million which can be carried forward indefinitely.
	In the event of a change in ownership, as defined under federal and state tax laws, our net operating loss and tax credit carryforwards may be subject to annual limitations. The annual limitations may result in the expiration of the net operating loss and tax credit carryforwards before utilization.
	The changes in the balance of gross unrecognized tax benefits, which exclude interest and penalties, for fiscal year ended December 31, 2014, 2013, and 2012, is as follows (in thousands):
	Unrecognized tax benefit as of December 31, 2011	$	15,472
	Tax positions related to current year:
	Additions for uncertain tax positions	5,087
	Tax positions related to prior year:
Additions for uncertain tax positions	80
Unrecognized tax benefit as of December 31, 2012	20,639
Tax positions related to current year:
Additions for uncertain tax positions	6,110
Tax positions related to prior year:
Decreases for uncertain tax positions	(81		)
Unrecognized tax benefit as of December 31, 2013	26,668
Tax positions related to current year:
Additions for uncertain tax positions	6,659
Tax positions related to prior year:
Decreases for uncertain tax positions	(260		)
Unrecognized tax benefit as of December 31, 2014	$	33,067
We account for uncertain tax positions pursuant to authoritative guidance based on a two-step approach to recognize and measure uncertain tax positions taken or expected to be taken in a tax return. We first determine whether it is more likely than not that a tax position will be sustained upon audit based on its technical merits. If a tax position meets the more-likely-than-not recognition threshold it is then measured to determine the amount of benefit to recognize in the financial statements. The tax position is measured as the largest amount of benefit that is more than 50 percent likely to be realized upon ultimate settlement. We adjust our uncertain tax positions due to changing facts and circumstances, such as the closing of a tax audit, or refinement of estimates due to new information. To the extent the final outcome of these matters is different than the amounts recorded, such differences will impact our tax provision in our Consolidated Statements of Operations in the period in which such determination is made.
During fiscal year 2014, the amount of gross unrecognized tax benefits increased by $6.4 million. The total amount of unrecognized tax benefits was $33.1 million as of December 31, 2014, all of which would impact our effective tax rate if recognized.  We have elected to recognize interest and penalties related to unrecognized tax benefits as a component of income tax expense. The penalties and interest accrued as of December 31, 2014 and 2013 are immaterial. We do not expect any significant changes to the amount of unrecognized tax benefits within the next twelve months.
We file U.S. federal, U.S. state, and non-U.S. tax returns. Our major tax jurisdictions are U.S. federal and the State of California. For U.S. federal and state tax returns, we are no longer subject to tax examinations for years before 2000. With few exceptions, we are no longer subject to examination by foreign tax authorities for years before 2007.

Net_Income_per_Share

Net Income per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
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 stock options, RSUs, MSUs 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):
		Year Ended December 31,
		2014		2013		2012
	Numerator:
	Net income	$	145,832	$	64,295	$	58,691
	Denominator:
	Weighted-average common shares outstanding, basic	80,754		80,551		80,529
	Dilutive effect of potential common stock	1,529		2,038		2,511
	Total shares, diluted	82,283		82,589		83,040
	Net income per share, basic	$	1.81	$	0.8	$	0.73
	Net income per share, diluted	$	1.77	$	0.78	$	0.71
	For the year ended December 31, 2014, 2013 and 2012, the anti-dilutive effect on net income per share from stock options, RSUs, MSUs and our employee stock purchase plan were not material.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information
	The supplemental cash flow information consists of the following (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Taxes paid	$	5,666	$	4,125	$	2,825
	Non-cash investing and financing activities:
	Fixed assets acquired with accounts payable or accrued liabilities	$	4,899	$	2,308	$	940
	Unclaimed merger consideration liability	$	—	$	—	$	1,575

Segments_and_Geographical_Info

Segments and Geographical Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [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 and gross profit.
	We have grouped our operations into two reportable segments which are also our reporting units: Clear Aligner segment and Scanner segment.
	•	Our Clear Aligner segment consists of our Invisalign System which includes Invisalign Full, Express/Lite, Teen, Assist, Vivera Retainers, along with our training and ancillary products for treating malocclusion.
	•	Our Scanner segment consists of intra-oral scanning systems and additional services available with the intra-oral 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):
		For the Year Ended December 31,
	Net Revenues	2014		2013		2012
	Clear Aligner
	Invisalign Full Products	$	585,721	$	497,507	$	434,432
	Invisalign Express Products	80,598		72,418		51,486
	Invisalign non-case revenues	46,230		44,724		30,663
	Scanner
	Scanners and Services	49,104		45,557		43,460
	Total net revenues	$	761,653	$	660,206	$	560,041
	Gross Profit
	Clear Aligner	$	562,889	$	484,835	$	405,970
	Scanners and Services	15,554		13,271		10,418
	Total gross profit	$	578,443	$	498,106	$	416,388
	Geographical Information
	Net revenues and tangible long-lived assets are presented below by geographic area (in thousands):
		For the Year Ended December 31,
		2014		2013		2012
	Net revenues 1:
	United States	$	532,569	$	491,410	$	427,929
	the Netherlands	156,817		122,494		105,942
	Other international	72,267		46,302		26,170
	Total net revenues	$	761,653	$	660,206	$	560,041
	1	Net revenues are attributed to countries based on location of where revenue is recognized.
		As of December 31,
		2014		2013
	Long-lived assets 2:
	United States	$	76,511	$	61,439
	Mexico	6,229		6,291
	the Netherlands	874		1,630
	Other international	6,511		6,383
	Total long-lived assets	$	90,125	$	75,743
	2	Long-lived assets are attributed to countries based on entity that owns the assets.

Schedule_II_Valuation_and_Qual

Schedule II: Valuation and Qualifying Accounts and Reserves	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II: Valuation and Qualifying Accounts and Reserves	SCHEDULE II: VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
		Balance at		Additions			Write			Charged to		Reclass			Balance at
		Beginning		(reductions)			offs			Other		from			End of Period
		of Period		to Costs						Accounts 1		Other
				and								Accounts
				Expenses
		(in thousands)
	Allowance for doubtful accounts and returns:
	Year ended December 31, 2012	$	1,500	$	4,417		$	(2,735	)	$	—	$	(15	)	$	3,167
	Year ended December 31, 2013	$	3,167	$	2,116		$	(3,550	)	$	—	$	—		$	1,733
	Year ended December 31, 2014	$	1,733	$	6,563		$	(6,733	)	$	—	$	—		$	1,563
	Valuation Allowance for deferred tax assets:
	Year ended December 31, 2012	$	20,224	$	8,507		$	(1,675	)	$	—	$	—		$	27,056
	Year ended December 31, 2013	$	27,056	$	9,806		$	(1,754	)	$	—	$	—		$	35,108
	Year ended December 31, 2014	$	35,108	$	(1,793	)	$	(817	)	$	—	$	—		$	32,498

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Business Description	Business Description
	Align Technology, Inc. (“We”, “Our”, or “Align”) was incorporated in April 1997 in Delaware and focuses on designing, manufacturing and marketing innovative, technology-rich products to help dental professionals achieve the clinical results they expect and deliver effective, convenient cutting-edge dental treatment options to their patients. We are headquartered in San Jose, California with offices worldwide.  Our international headquarters are located in Amsterdam, the Netherlands. We have two operating segments, (1) Clear Aligner, known as the Invisalign System, and (2) Scanners and Services ("Scanner"), known as the iTero intra-oral scanner and OrthoCAD services.
Basis of presentation and preparation	Basis of presentation and preparation
	The consolidated financial statements include the accounts of Align and our wholly-owned subsidiaries after elimination of intercompany transactions and balances.  Certain amounts in prior periods have been reclassified to conform with the current period presentation. These reclassifications had no impact on previously reported gross profit or financial position.
	In connection with the preparation of the consolidated financial statements, we evaluated events subsequent to the balance sheet date through the financial statement issuance date and determined that all material transactions have been recorded and disclosed properly.
Use of estimates	Use of estimates
	The preparation of financial statements in conformity with accounting principles generally accepted 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, intangible assets and goodwill, useful lives of intangible assets and property and equipment, stock-based compensation, revenue recognition, 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.
Fair value of financial instruments	Fair value of financial instruments
	The carrying amounts of our cash, accounts receivable, accounts payable and other current liabilities approximate their fair value.
	We measure our cash equivalents, marketable securities, and our Israeli severance fund at fair value.  Fair value is 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.  Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement:
	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.
	Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.
Cash and cash equivalents	Cash and cash equivalents
	We consider currency on hand, demand deposits, time deposits, and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents.  Cash and cash equivalents are held in various financial institutions in the U.S. and internationally.
Restricted cash	Restricted cash
	Our restricted cash balance as of December 31, 2014 was $3.8 million, of which $3.6 million was classified as a long term asset and $0.2 million as a current asset. Our restricted cash balance as of December 31, 2013 was $4.0 million and was classified as a long term asset. The restricted cash primarily consisted of funds reserved for legal requirements.
Marketable Securities	Marketable securities
	We invest primarily in money market funds, commercial paper, corporate bonds, U.S. government agency bonds, asset-backed securities, municipal bonds, U.S. dollar dominated foreign corporate bonds, U.S. government treasury bonds and certificates of deposits.
	Marketable securities are classified as available-for-sale and are carried at fair value.  Marketable securities classified as current assets have maturities of less than one year.  Unrealized gains or losses on such securities are included in accumulated other comprehensive income, net in stockholders’ equity.  Realized gains and losses from maturities of all such securities are reported in earnings and computed using the specific identification cost method.  Realized gains or losses and charges for other-than-temporary declines in value, if any, on available-for-sale securities are reported in Interest and other income (expense), net as incurred.  We periodically evaluate these investments for other-than-temporary impairment.
Foreign currency	Foreign currency
	For our international subsidiaries where the U.S. dollar is the functional currency, we analyze on an annual basis or more often if necessary, if a significant change in facts and circumstances indicate that the primary economic currency has changed.  Adjustments from translating certain European and Asia Pacific subsidiaries’ financial statements from the local currency to the U.S. dollar are recorded as a separate component of accumulated other comprehensive income (loss), net in the stockholders’ equity section of the Consolidated Balance Sheet.  This foreign currency translation adjustment reflects the translation of the balance sheet at period end exchange rates, and the income statement at an average exchange rate in effect during the period.  As of December 31, 2014 and 2013, there were no material amounts in accumulated other comprehensive income, net related to the translation of our foreign subsidiaries’ financial statements.
	Our other international entities operate in a U.S. dollar functional currency environment, and therefore, the foreign currency assets and liabilities are remeasured into the U.S. dollar at current exchange rates except for non-monetary assets and liabilities which are remeasured at historical exchange rates.  Revenues and expenses are generally remeasured at an average exchange rate in effect during each period.  Gains or losses from foreign currency remeasurement are included in Interest and other income (expense), net. For the year ended December 31, 2014, we had foreign currency net losses of $3.8 million. For year ended December 31, 2013, foreign currency gains and losses were not significant
Certain risks and uncertainties	Certain risks and uncertainties
	Our operating results depend to a significant extent on our ability to market and develop our products.  The life cycles of our products are difficult to estimate due, in part, to the effect of future product enhancements and competition.  Our inability to successfully develop and market our products as a result of competition or other factors would have a material adverse effect on our business, financial condition and results of operations.
	Our cash and investments are held primarily by two financial institutions. Financial instruments which potentially expose us to concentrations of credit risk consist primarily of cash equivalents, marketable securities and accounts receivable.  We invest excess cash primarily in money market funds of major financial institutions, U.S. government agencies, U.S. dollar dominated foreign corporate bonds and domestic corporate bonds.  If the carrying value of our investments exceeds the fair value, and the decline in fair value is deemed to be other-than-temporary, we will be required to write down the value of our investments, which could materially harm our results of operations and financial condition.  Moreover, the performance of certain securities in our investment portfolio correlates with the credit condition of the U.S. economy.  We provide credit to customers in the normal course of business.  Collateral is not required for accounts receivable, but ongoing evaluations of customers’ credit worthiness are performed.  We maintain reserves for potential credit losses and such losses have been within management’s expectations.  No individual customer accounted for 10% or more of our accounts receivable at December 31, 2014 or 2013, or net revenues for the year ended December 31, 2014, 2013, or 2012.
	In the U.S., the Food and Drug Administration (“FDA”) regulates the design, manufacture, distribution, pre-clinical and clinical study, clearance and approval of medical devices.  Products developed by us may require approvals or clearances from the FDA or other international regulatory agencies prior to commercialized sales.  There can be no assurance that our products will receive any of the required approvals or clearances.  If we were denied approval or clearance or such approval was delayed, it may have a material adverse impact on us.
	We have manufacturing operations located outside the U.S.  We currently rely on our manufacturing facility in Costa Rica to prepare digital treatment plans using a sophisticated, internally developed computer-modeling program.  In addition, we manufacture our clear aligners and distribute our intra-oral scanners at our facility in Juarez, Mexico, and we produce our handheld scanner wand in Or Yehuda, Israel.  Our reliance on international operations exposes us to related risks and uncertainties, including difficulties in staffing and managing international operations such as hiring and retaining qualified personnel; controlling production volume and quality of manufacture; political, social and economic instability, particularly as a result of increased levels of violence in Juarez, Mexico and Israel; interruptions and limitations in telecommunication services; product and material transportation delays or disruption; trade restrictions and changes in tariffs; import and export license requirements and restrictions; fluctuations in foreign currency exchange rates; and potential adverse tax consequences.  If any of these risks materialize, our international manufacturing operations, as well as our operating results, may be harmed.
	We purchase certain inventory from sole suppliers.  Additionally, we rely on a limited number of hardware manufacturers.  The inability of any supplier or manufacturer to fulfill our supply requirements could materially and adversely impact our future operating results.
Inventories	Inventories
	Inventories are valued at the lower of cost or market, with cost computed using either standard cost (which approximates actual cost) or average and actual cost on a first-in-first-out basis.  Excess and obsolete inventories are determined primarily based on future demand forecasts, and write-downs of excess and obsolete inventories are recorded as a component of cost of revenues.
Property, plant and equipment	Property, plant and equipment
	Property, plant and equipment are stated at historical cost less accumulated depreciation and amortization.  Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, generally three to ten years. We amortize leasehold improvements over the shorter of the remaining lease term or the estimated useful lives of the assets. We depreciate buildings over periods up to 20 years. Land is not depreciated. Construction in progress ("CIP") is related to the construction or development of property (including land) and equipment that have not yet been placed in service for their intended use.  Upon sale or retirement, the asset’s cost and related accumulated depreciation are removed from the general ledger and any related gains or losses are reflected in operating expenses.  Maintenance and repairs are expensed as incurred.
Goodwill and finite-lived purchased intangible assets	Goodwill and finite-lived acquired intangible assets
	Goodwill represents the excess of the purchase price paid over the fair value of tangible and identifiable intangible net assets acquired in business combinations and is allocated to the respective reporting units based on relative synergies generated.
	Our intangible assets primarily consist of intangible assets acquired as part of the Cadent acquisition.  These assets are amortized using the straight-line method over their estimated useful lives ranging from one to fifteen years, reflecting the period in which the economic benefits of the assets are expected to be realized.
Impairment of goodwill and long-lived assets	Impairment of goodwill and long-lived assets
	Goodwill
	We evaluate goodwill for impairment at least annually on November 30th or more frequently if indicators are present, an event occurs or circumstances changes that suggest an impairment may exist and that it would more likely than not reduce the fair value of a reporting unit below its carrying amount.  The allocation of goodwill to the respective reporting unit is based on relative synergies generated as a result of an acquisition.
	We perform an initial assessment of qualitative factors to determine whether the existence of events and circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. In performing the qualitative assessment, we identify and consider the significance of relevant key factors, events, and circumstances that affect the fair value of our reporting units. These factors include external factors such as macroeconomic, industry, and market conditions, as well as entity-specific factors, such as our actual and planned financial performance. We also give consideration to the difference between the reporting unit fair value and carrying value as of the most recent date a fair value measurement was performed. If, after assessing the totality of relevant events and circumstances, we determine that it is more likely than not that the fair value of the reporting unit exceeds its carrying value and there is no indication of impairment, no further testing is performed; however, if we conclude otherwise, the first step of the two-step impairment test is performed by estimating the fair value of the reporting unit and comparing it with its carrying value, including goodwill.
	Step one of the goodwill impairment test consists of a comparison of the fair value of a reporting unit against its carrying amount, including the goodwill allocated to each reporting unit.  We determine the fair value of our reporting units based on the present value of estimated future cash flows under the income approach of the reporting units as well as various price or market multiples applied to the reporting unit's operating results along with the appropriate control premium under the marketing approach, both of which are classified as level 3 within the fair value hierarchy (as described in Note 2 in our consolidated financial statements).  If the carrying amount of the reporting unit is in excess of its fair value, step two requires the comparison of the implied fair value of the reporting unit’s goodwill against the carrying amount of the reporting unit’s goodwill.  Any excess of the carrying value of the reporting unit’s goodwill over the implied fair value of the reporting unit’s goodwill is recorded as an impairment loss.
	During March 2013, changes in the competitive environment for intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists ("GPs") in North America, caused us to lower our expectations for growth and profitability for our Scanner reporting unit. As a result, we determined that goodwill related only to our Scanner reporting unit should be tested for impairment as of March 31, 2013 due to these facts and circumstances which would more likely than not reduce the fair value of our Scanner reporting unit below its carrying amount. There was no triggering event related to the Clear Aligner goodwill. Refer to Note 5 for details of the impairment analysis.
	The remaining goodwill is entirely attributable to our Clear Aligner reporting unit. During the fourth quarter of fiscal 2014, we performed the annual goodwill impairment testing using the qualitative approach discussed above and found no impairment as the fair value of our Clear Aligner reporting unit was significantly in excess of the carrying value.
	Finite-lived intangible assets and long-lived assets
	We evaluate long-lived assets (including finite-lived intangible assets) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable.  An asset or asset group is considered impaired if its carrying amount exceeds the future undiscounted net cash flows the asset or asset group is expected to generate.  If an asset or asset group is considered to be impaired, the impairment to be recognized is calculated as the amount by which the carrying amount of the asset or asset group exceeds its fair market value.  Our estimates of future cash flows attributable to our long-lived assets require significant judgment based on our historical and anticipated results and are subject to many factors. Factors we consider important which could trigger an impairment review include significant negative industry or economic trends, significant loss of customers and changes in the competitive environment. In 2013, we used a DCF approach, utilizing harvest model, to estimate the fair value of a reporting unit, which we believe is the most reliable indicator of fair value of a business, and is most consistent with the approach of a marketplace participant would use. The estimation of fair value utilizing a DCF approach includes numerous uncertainties which require our significant judgment when making assumptions of expected growth rates and the selection of discount rates, as well as assumptions regarding general economic and business conditions, and the structure that would yield the highest economic value, among other factors. Key assumptions used in measuring the fair values of Scanner reporting unit included the discount rate (based on the weighted-average cost of capital) and revenue growth. The fair value of Scanner’s trademark was determined using a risk-adjusted DCF model under the relief-from-royalty method. The royalty rate used was based on a consideration of market rates. The fair value of Scanner’s finite-lived customer relationships was determined using a DCF model under the multi-period excess earnings method. We recorded a long-lived asset impairment in the quarter ended March 31, 2013 due to changes in the competitive environment for our intra-oral scanners, including announcements from our competitors of new low-priced scanners targeted at orthodontists and general practitioner dentists in North America. There was no triggering event related to the Clear Aligner asset group. Refer to Note 5 for details of the impairment analysis.
	There were no further triggering events in 2014 that would cause further impairments of our long-lived assets.
Development costs for internal use software	Development costs for internal use software
	Internally developed software includes enterprise-level business software that we are customizing to meet our specific operational needs.
Product Warranty	Product Warranty
	Clear Aligner
	We warrant our Invisalign products against material defects until the Invisalign case is complete. We accrue for warranty costs in cost of net revenues upon shipment of products. The amount of accrued estimated warranty costs is primarily based on historical experience as to product failures as well as current information on replacement costs.  Actual warranty costs could differ materially from the estimated amounts. We regularly review the accrued balances and update these balances based on historical warranty cost trends.
	Scanners and Services
	We warrant our intra-oral scanners for a period of one year, which include materials and labor.  We accrue for these warranty costs based on average historical repair costs.  An extended warranty may be purchased for additional fees.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts and Returns
	We maintain allowances for doubtful accounts, for customers that are not able to make payments, and for sales returns.  We periodically review these allowances, including an analysis of the customers’ payment history and information regarding the customers’ creditworthiness, as well as historical sales returns as a percentage of revenue.  Actual write-offs have not materially differed from the estimated allowance.
Revenue recognition	Revenue Recognition
	We measure and allocate revenue according to the accounting guidance for multiple-deliverable revenue arrangements in Accounting Standards Update (“ASU”) 2009-13, Multiple-Deliverable Revenue Arrangements-a consensus of the Financial Accounting Standard Board (“FASB”) Emerging Issues Task Force.
	Multiple-Element Arrangements (“MEAs”): Arrangements with customers may include multiple deliverables, including any combination of products/equipment and services.  The deliverables included in the MEAs are separated into more than one unit of accounting when (i) the delivered product/equipment has value to the customer on a stand-alone basis, and (ii) delivery of the undelivered service element(s) is probable and substantially in our control.  Arrangement consideration is then allocated to each unit, delivered or undelivered, based on the relative selling price (“RSP”) of each unit of accounting based first on vendor-specific objective evidence (“VSOE”) if it exists, second on third-party evidence (“TPE”) if it exists, and on best estimated selling price (“BESP”) if neither VSOE or TPE exist.
	•	VSOE – In most instances, products are sold separately in stand-alone arrangements.  Services are also sold separately through renewals of contracts with varying periods.  We determine VSOE based on its pricing and discounting practices for the specific product or service when sold separately, considering geographical, customer, and other economic or marketing variables, as well as renewal rates or stand-alone prices for the service element(s).
	•	TPE – If we cannot establish VSOE of selling price for a specific product or service included in a multiple-element arrangement, we use third-party evidence of selling price. We determine TPE based on sales of comparable amount of similar products or service offered by multiple third parties considering the degree of customization and similarity of product or service sold.
	•	BESP – The best estimated selling price represents the price at which we would sell a product or service if it were sold on a stand-alone basis.  When VSOE or TPE do not exist for all elements, we determine BESP for the arrangement element based on sales, cost and margin analysis, as well as other inputs based on its pricing practices.  Adjustments for other market and Company-specific factors are made as deemed necessary in determining BESP.
	Provisions for discounts and rebates to customers are provided for in the same period that the related product sales are recorded based upon historical discounts and rebates.
	Clear Aligner
	We enter into arrangements (“treatment plans”) that involve multiple future product deliverables.  Invisalign Full, Invisalign Teen, and Invisalign Assist include up to three optional case refinements. Case refinement is a finishing tool used to adjust a patient's teeth to the desired final position.  Case refinement may be elected by the dental professional at any time during treatment however it is generally ordered in the last stages of orthodontic treatment.  Beginning June 15, 2013, Invisalign Full and Invisalign Teen also include up to three optional mid-course corrections. Mid-course correction is a treatment adjustment during active treatment if the case is not tracking to the original treatment plan or goals. Mid-course correction gives doctors the ability to "adjust course' based on the needs of the individual patient. Invisalign Teen also includes up to six optional replacement aligners in the price of the product and may be ordered any time throughout treatment.
	We determined that our treatment plans, except Invisalign Assist with progress tracking, comprise the following deliverables which also represent separate units of accounting: single-batched aligners, case refinement, mid-course correction and replacement aligners.  We allocate revenue for each treatment plan based on each unit's relative selling price based on BESP and recognize the revenue upon the delivery of each unit in the treatment plan. We regularly review our estimates of selling price and maintain internal controls over the establishment and update of these estimates.
	For Invisalign Assist with the progress tracking feature, aligners and services are provided to the dental professional every nine stages (“a batch”). We estimate the number of batches which are expected to be shipped for each case based upon our historical experience.  The amounts allocated to this deliverable are recognized on a prorated basis as each batch is shipped.
	Prior to 2013, the Vivera Retainer included four shipments per year, and revenue was recognized ratably as each shipment occurred. In the first quarter of 2013, we consolidated Vivera Retainer product shipments down to one shipment per year.
	Scanners and Services
	We recognize revenues from the sales of iTero intra-oral scanners and CAD/CAM services. CAD/CAM services include scanning services, extended warranty for the intra-oral scanners, a range of iTero restorative services, and OrthoCAD services such as OrthoCAD iRecord. We sell intra-oral scanners and services through both our direct sales force and distribution partners.  The intra-oral scanner sales price includes one year of warranty, and for additional fees, the customer may select an unlimited scanning service agreement over a fixed period of time or extended warranty periods.  Revenue is recognized when persuasive evidence of the arrangement exists, the price is fixed or determinable, collectability is reasonably assured, title and risk of loss has passed to customers based on the shipping terms, no significant obligations remain, and allowances for discounts, returns, and customer incentives can be reliably estimated. When intra-oral scanners are sold with either an unlimited scanning service agreement and/or extended warranty, we allocate revenue based on each element's relative selling price.  We estimate the selling price of each element, as if it is sold on a stand-alone basis, taking into consideration historical prices as well as our discounting strategies. Scanner revenue, net of related discounts and allowances, is recognized when products or equipment have been shipped, installed and on-site training completed.   For certain distributors who provide installation and training to the customer, we recognize scanner revenue when the intra-oral scanner is shipped to the distributor assuming all of the other revenue recognition criteria have been met.
	Discounts are deducted from revenue at the time of sale or when the discount is offered, whichever is later, and free cases or training is included as a deliverable in the multiple-element arrangement assessment. Returns of products, excluding warranty related returns, are infrequent and insignificant.
	Service revenue, including iTero restorative and all OrthoCAD services are recognized upon delivery or ratably over the contract term as the specified services are performed. If a customer selects a pay per use basis for scanning service fees, the revenue is recognized as the service is provided.
	We offer customers an option to purchase extended warranties on certain products. We recognize revenue on these extended warranty contracts ratably over the life of the contract. The costs associated with these extended warranty contracts are recognized when incurred.
Shipping and Handling Costs	Shipping and Handling Costs
	Shipping and handling charges to customers are included in net revenues, and the associated costs incurred are recorded in cost of revenues.
Legal Proceedings and Litigations	Legal Proceedings and Litigations
	We are involved in legal proceedings on an ongoing basis. If we believe that a loss arising from such matters is probable and can be reasonably estimated, we accrue the estimated liability in our financial statements. If only a range of estimated losses can be determined, we accrue an amount within the range that, in our judgment, reflect the most likely outcome; if none of the estimates within that range is a better estimate than any other amount, we accrue the low end of the range.
Research and development	Research and development
	Research and development expense is expensed as incurred and includes the costs associated with the research and development of new products and enhancements to existing products. These costs primarily include compensation costs, including stock-based compensation expense, outside consulting expenses, costs associated with conducting clinical and pre-commercialization trial and testing, allocations of corporate overhead expenses including facilities and IT costs, equipment costs and depreciation and amortization.
Advertising costs	Advertising costs
	The cost of advertising and media is expensed as incurred. For the year ended December 31, 2014, 2013 and 2012 advertising costs totaled $26.9 million, $26.0 million and $23.6 million, respectively.
Common Stock Repurchase	Common stock repurchase
	We repurchase our own common stock from time to time in the open market when our Board of Directors approve a stock repurchase program. We account for these repurchases under the accounting guidance for equity where we allocate the total repurchase value that are in excess over par between additional paid in capital and retained earnings. All shares repurchased are retired.
Operating Leases	Operating leases
	We currently lease office spaces, automobiles and equipment under operating leases with original lease periods of up to 9 years.  Certain of these leases have free or escalating rent payment provisions and lease incentives provided by the landlord. We recognize rent expense under such leases on a straight-line basis over the term of the lease as certain leases have adjustments for market provisions.
Income taxes	Income taxes
	We make certain estimates and judgments in determining income tax expense for financial statement purposes. These estimates and judgments occur in the calculation of certain tax assets and liabilities, which arise from differences in the timing of recognition of revenue and expense for tax and financial statement purposes.
	As part of the process of preparing our Consolidated Financial Statements, we are required to estimate our income taxes in each of the jurisdictions in which we operate. This process involves us estimating our current tax exposure under the applicable tax laws and assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included in our Consolidated Balance Sheets.
	We account for uncertainty in income taxes pursuant to authoritative guidance based on a two-step approach to recognize and measure uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained on audit based on its technical merits, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement. We adjust reserves for our uncertain tax positions due to changing facts and circumstances, such as the closing of a tax audit, or refinement of estimates due to new information. To the extent that the final outcome of these matters is different than the amounts recorded, such differences will impact our tax provision in our Consolidated Statements of Operations in the period in which such determination is made.
	We assess the likelihood that we will be able to realize our deferred tax assets. Should there be a change in our ability to realize our deferred tax assets, our tax provision would increase in the period in which we determine that it is more likely than not that we cannot realize our deferred tax assets. We consider all available evidence, both positive and negative, including historical levels of income, expectations and risks associated with estimates of future taxable income and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. If it is more likely than not that we will not realize our deferred tax assets, we will increase our provision for taxes by recording a valuation allowance against the deferred tax assets that we estimate will not ultimately be realizable. The available positive evidence at December 31, 2014 included historical operating profits and a projection of future income sufficient to realize most of our remaining deferred tax assets. As of December 31, 2014, it was considered more likely than not that our deferred tax assets would be realized with the exception of certain foreign loss carryovers as we are unable to forecast sufficient future profits to realize the deferred tax assets.
	As of December 31, 2014, U.S. income taxes and foreign withholding taxes associated with the repatriation of undistributed earnings of foreign subsidiaries were not provided for on a cumulative total of $260.9 million. We intend to reinvest these earnings indefinitely in our foreign subsidiaries. If these earnings were distributed in the form of dividends or otherwise, or if the shares of the relevant foreign subsidiaries were sold or otherwise transferred, we would be subject to additional U.S. income taxes subject to an adjustment for foreign tax credit, and foreign withholding taxes. Determination of the amount of unrecognized deferred income tax liability related to these earnings is not practicable.
	Accounting guidance for stock-based compensation prohibits recognition of a deferred income tax asset for excess tax benefits due to stock option exercises that have not yet been realized through a reduction in income taxes payable. We follow the tax law ordering method to determine when excess tax benefits have been realized and consider only the direct impacts of awards when calculating the amount of windfalls or shortfalls.
Stock-based compensation	Stock-based compensation
	We recognize stock-based compensation cost for only those shares ultimately expected to vest on a straight-line basis over the requisite service period of the award. We use the Black-Scholes option pricing model to determine the fair value of stock options and employee stock purchase plan shares. We estimate the fair value of market-performance based restricted stock units using a Monte Carlo simulation model which requires the input of assumptions, including expected term, stock price volatility and the risk-free rate of return.  In addition, judgment is also required in estimating the number of stock-based awards that are expected to be forfeited.  Forfeitures are estimated based on historical experience at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these estimates involve inherent uncertainties and the application of management’s judgment.  As a result, if factors change and we use different assumptions, our stock-based compensation expense could be materially different in the future.
Consolidation of Variable Interest Entities	Consolidation of Variable Interest Entities
	For an entity in which we have variable interests, we focus on identifying which entity has the power to direct the activities that most significantly impact the variable interest entity’s economic performance and which enterprise has the obligation to absorb losses or the right to receive benefits from the variable interest entity. If we are the primary beneficiary of a variable interest entity, the assets, liabilities, and results of operations of the variable interest entity will be included in our Consolidated Financial Statements. For fiscal year 2014, 2013 and 2012, we did not have any material variable interest entities and did not consolidate any variable interest entities, because we are not a primary beneficiary.
Medical Device Excise Tax	Medical Device Excise Taxes
	In accordance with the Patient Protection and Affordable Care Act, effective January 1, 2013, we began to incur an excise tax on sales of medical devices in the U.S. In March 2014, we were informed by IRS that our aligners are not subject to the medical device excise tax ("MDET") which we had been paying and expensing in general and administrative expenses in the consolidated statements of operations since January 1, 2013; however, our scanners are still subject to the MDET. Beginning in March 2014, we ceased expensing and paying the MDET for aligners. We are currently in process of claiming a $6.8 million refund of MDET paid in 2013 related to our aligners; however, because this claim is subject to review and approval by the IRS, we have not recorded a receivable as the outcome of the audit is uncertain. Any future changes in the applicability of the MDET as it applies to us or refunds of amounts previously paid will be recorded as an additional expense or a credit to the consolidated statement of operations in the period in which is becomes probable and reasonably estimable.
Comprehensive income	Comprehensive income
	Comprehensive income includes all changes in equity during a period from non-owner sources. Comprehensive income, including unrealized gains and losses on available-for-sale securities and foreign currency translation adjustments, are reported net of their related tax effect.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-09, “Revenue from Contracts with Customers,” requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The updated standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. Early adoption is not permitted. The updated standard becomes effective for us in the first quarter of fiscal 2017. We have not yet selected a transition method and we are currently evaluating the effect that the updated standard will have on our consolidated financial statements and related disclosures.
Earnings Per Share, Policy	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 stock options, RSUs, MSUs and our ESPP.
Reclassification, Policy [Policy Text Block]	Out of period adjustment
	In 2013, we recorded an out of period correction that resulted in decreases in cost of net revenues of approximately $1.7 million and operating expense of $0.7 million offset in part by an increase in the provision for income taxes of $0.5 million. We do not believe the increase of $1.9 million to net income related to the out of period adjustment is material to the consolidated financial statements for the fiscal year ended December 31, 2013 or to any prior years' consolidated financial statements.
	In 2014, we recorded an out of period correction that resulted in an increase in the provision for income taxes of $1.8 million. We do not believe the decrease to net income related to the out of period adjustment is material to the consolidated financial statements for the fiscal year ended December 31, 2014 or to any prior years' consolidated financial statements.

Marketable_Securities_and_Fair1

Marketable Securities and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Short-Term And Long-Term Marketable Securities	As of December 31, 2014 and 2013, the estimated fair value of our short-term and long-term investments, classified as available for sale, are as follows (in thousands):
	Short-term
	31-Dec-14	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	Commercial paper	$	33,998		$	—		$	—		$	33,998
	Corporate bonds	152,055			27			(116		)	151,966
	U.S. dollar dominated foreign corporate bonds	901			—			—			901
	Municipal securities	9,147			13			—			9,160
	U.S. government agency bonds	41,574			14			(1		)	41,587
	U.S. government treasury bonds	15,770			7			—			15,777
	Certificates of Deposit	1,398			—			—			1,398
	Total Marketable Securities, Short-Term	$	254,843		$	61		$	(117	)	$	254,787
	Long-term
	31-Dec-14	Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	U.S. government agency bonds	$	48,233		$	12		$	(28	)	$	48,217
	Corporate bonds	57,195			6			(112		)	57,089
	U.S. dollar dominated foreign corporate bonds	523			—			(2		)	521
	U.S. government treasury bonds	20,814			5			(6		)	20,813
	Municipal securities	9,552			5			(6		)	9,551
	Asset-backed securities	11,713			—			(12		)	11,701
	Total Marketable Securities, Long-Term	$	148,030		$	28		$	(166	)	$	147,892
	Short-term
	December 31, 2013	Amortized			Gross			Gross			Fair Value
		Cost			Unrealized			Unrealized
					Gains			Losses
	Commercial paper	$	54,318		$	10		$	—		$	54,328
	Corporate bonds	29,079			10			(4		)	29,085
	U.S. dollar dominated foreign corporate bonds	13,959			12			—			13,971
	Municipal securities	7,006			11			(3		)	7,014
	U.S. government agency bonds	16,693			10			—			16,703
	Asset-backed securities	5,937			2			—			5,939
	Total Marketable Securities, Short-Term	$	126,992		$	55		$	(7	)	$	127,040
	Long-term
	December 31, 2013	Amortized			Gross			Gross			Fair Value
		Cost			Unrealized			Unrealized
					Gains			Losses
	U.S. government agency bonds	$	38,138		$	1		$	(21	)	$	38,118
	Corporate bonds	23,308			14			(9		)	23,313
	U.S. dollar dominated foreign corporate bonds	19,485			27			(17		)	19,495
	U.S. government treasury bonds	6,916			3			—			6,919
	Municipal securities	8,326			13			(8		)	8,331
	Asset-backed securities	5,800			4			(2		)	5,802
	Total Marketable Securities, Long-Term	$	101,973		$	62		$	(57	)	$	101,978
Marketable Securities	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 maturity as of December 31, 2014 and 2013  (in thousands):
			December 31,			December 31,
			2014			2013
	One year or less		$	254,787		$	127,040
	Due in greater than one year		147,892			101,978
	Total available for short-term and long-term marketable securities		$	402,679		$	229,018
Financial Assets Measured At Fair Value On A Recurring Basis	The following tables summarizes our financial assets measured at fair value on a recurring basis as of December 31, 2014 and 2013 (in thousands):
	Description	Balance as of			Quoted Prices in			Significant Other
		December 31, 2014			Active Markets for			Observable Inputs
					Identical Assets			(Level 2)
					(Level 1)
	Cash equivalents:
	Money market funds	$	80,786		$	80,786		$	—
	Commercial paper	21,997			—			21,997
	Corporate bonds	1,745			—			1,745
	Short-term investments:
	Commercial paper	33,998			—			33,998
	Corporate bonds	151,966			—			151,966
	U.S. dollar denominated foreign corporate bonds	901			—			901
	Municipal securities	9,160			—			9,160
	U.S. government agency bonds	41,587			—			41,587
	U.S. government treasury bonds	15,777			15,777			—
	Certificate of Deposits	1,398			—			1,398
	Long-term investments:
	Corporate bonds	57,089			—			57,089
	U.S. government agency bonds	48,217			—			48,217
	U.S. dollar denominated foreign corporate bonds	521			—			521
	U.S. government treasury bonds	20,813			20,813			—
	Municipal securities	9,551			—			9,551
	Asset-backed securities	11,701			—			11,701
	Long-term other assets:
	Israeli funds	2,307			—			2,307
		$	509,514		$	117,376		$	392,138
	Description	Balance as of			Quoted Prices in			Significant Other
		December 31, 2013			Active Markets for			Observable Inputs
					Identical Assets			(Level 2)
					(Level 1)
	Cash equivalents:
	Money market funds	$	143,540		$	143,540		$	—
	Commercial paper	15,398			—			15,398
	Short-term investments:
	Commercial paper	54,328			—			54,328
	Corporate bonds	29,085			—			29,085
	U.S. dollar denominated foreign corporate bonds	13,971			—			13,971
	Municipal securities	7,014			—			7,014
	U.S. government agency bonds	16,703			—			16,703
	Asset-backed securities	5,939			—			5,939
	Long-term investments:
	Corporate bonds	23,313			—			23,313
	U.S. government agency bonds	38,118			—			38,118
	U.S. dollar denominated foreign corporate bonds	19,495			—			19,495
	U.S. government treasury bonds	6,919			6,919			—
	Municipal securities	8,331			—			8,331
	Asset-backed securities	5,802			—			5,802
	Long-term other assets:
	Israeli funds	2,193			—			2,193
		$	390,149		$	150,459		$	239,690

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands):
		December 31,
		2014				2013
	Raw materials	$	8,143			$	5,172
	Work in process	2,970				4,241
	Finished goods	4,815				4,555
	Total Inventories	$	15,928			$	13,968
Property and Equipment	Property, plant and equipment consist of the following (in thousands):
			December 31,
			2014				2013
	Clinical and manufacturing equipment		$	107,707			$	104,373
	Computer hardware		24,092				24,851
	Computer software		22,044				21,286
	Furniture and fixtures		7,386				7,275
	Leasehold improvements		15,358				14,996
	Building		1,868				1,868
	Land		1,162				1,162
	CIP		18,310				5,438
	Total		197,927				181,249
	Less: Accumulated depreciation and amortization and impairment charges 1		(107,802		)		(105,506		)
	Total Property, plant and equipment, net		$	90,125			$	75,743
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands):
		December 31,
		2014				2013
	Accrued payroll and benefits	$	44,610			$	43,029
	Accrued sales rebate	11,110				10,100
	Accrued sales and marketing expenses	5,979				3,893
	Accrued accounts payable	5,736				4,053
	Accrued sales tax and value added tax	5,456				6,215
	Accrued warranty	3,148				3,104
	Accrued professional fees	2,494				1,892
	Accrued income taxes	2,027				1,205
	Other accrued liabilities	7,320				6,854
	Total Accrued Liabilities	$	87,880			$	80,345
Warranty accrual	Warranty accrual as of December 31, 2014 and 2013 consists of the following activity (in thousands):
	Warranty accrual, December 31, 2012	$	4,050
	Charged to cost of revenues	2,850
	Actual warranty expenditures	(3,796		)
	Warranty accrual, December 31, 2013	3,104
	Charged to cost of revenues	1,990
	Actual warranty expenditures	(1,946		)
	Warranty accrual, December 31, 2014	$	3,148

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The change in the carrying value of goodwill for the year ended December 31, 2014 by our reportable segments, which are also our reporting units, are as follows (in thousands):
		Clear Aligner				Scanners and				Total
						Services
	Balance as of December 31, 2012	$	58,543			$	40,693			$	99,236
	Goodwill from ICA acquisition	3,558				—				3,558
	Impairment of goodwill	—				(40,693		)		(40,693		)
	Adjustments 1	(478		)		—				(478		)
	Balance as of December 31, 2013	61,623				—				61,623
	Goodwill from ICA acquisition	—				—				—
	Adjustments 1	(254		)		—				(254		)
	Balance as of December 31, 2014	$	61,369			$	—			$	61,369
	1	The adjustments to goodwill were a result of foreign currency translation.
Schedule Of Amortized Intangible Assets	ntangible assets arising either as a direct result from the Cadent acquisition or individually acquired are being amortized as follows (in thousands):
		Weighted Average Amortization Period (in years)		Gross Carrying Amount as of				Accumulated				Impairment Charge			Net Carrying
				December 31, 2014				Amortization							Value as of
															31-Dec-14
	Trademarks	15		$	7,100			$	(1,354	)		$	(4,179	)	$	1,567
	Existing technology	13		12,600				(3,015		)		(4,328		)	5,257
	Customer relationships	11		33,500				(9,095		)		(10,751		)	13,654
	Other	8		285				(76		)		—			209
	Total Intangible Assets			$	53,485			$	(13,540	)		$	(19,258	)	$	20,687
		Weighted Average Amortization Period (in years)		Gross Carrying				Accumulated				Impairment Charge			Net Carrying
				Amount as of				Amortization							Value as of
				31-Dec-13											31-Dec-13
	Trademarks	15		$	7,100			$	(1,100	)		$	(4,179	)	$	1,821
	Existing technology	13		12,600				(2,236		)		(4,328		)	6,036
	Customer relationships	11		33,500				(7,112		)		(10,751		)	15,637
	Other	8		285				(40		)		—			245
	Total Intangible Assets			$	53,485			$	(10,488	)		$	(19,258	)	$	23,739
Schedule of Future Amortization For Finited-Lived Intangible Assets	The total estimated annual future amortization expense for these acquired intangible assets as of December 31, 2014 is as follows (in thousands):
	Fiscal Year
	2015	$	2,600
	2016	2,600
	2017	2,600
	2018	2,600
	2019	2,600
	Thereafter	7,687
	Total	$	20,687

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Lease Payments	Minimum future lease payments for non-cancelable leases as of December 31, 2014, are as follows (in thousands):
	Fiscal Year	Operating leases
	2015	$	9,130
	2016	8,293
	2017	4,659
	2018	1,545
	2019	209
	Thereafter	210
	Total minimum lease payments	$	24,046

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Stock-based Compensation Expense	The stock-based compensation related to all of our stock-based awards and employee stock purchases for the year ended December 31, 2014, 2013 and 2012 is as follows (in thousands):
		For the Year Ended December 31,
		2014				2013				2012
	Cost of net revenues	$	3,616			$	2,565			$	1,843
	Sales and marketing	11,646				7,093				5,581
	General and administrative	17,979				13,261				10,361
	Research and development	6,582				3,519				3,698
	Total stock-based compensation	$	39,823			$	26,438			$	21,483
Stock Option Activity	Activity for the year ended December 31, 2014, under the stock option plans are set forth below (in thousands, except years and per share amounts):
		Stock Options
		Number of			Weighted				Weighted Average		Aggregate
		Shares			Average				Remaining		Intrinsic
		Underlying			Exercise				Contractual Term		Value
		Stock Options			Price per Share				(in years )
	Outstanding as of December 31, 2013	1,321			16.08
	Granted	—			—
	Exercised	(648	)		16.58
	Cancelled or expired	(5	)		18.32
	Outstanding as of December 31, 2014	668			$	15.57			2.92		$	26,933
	Vested and expected to vest at December 31, 2014	668			$	15.57			2.92		$	26,930
	Exercisable at December 31, 2014	655			$	15.43			2.92		$	26,504
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Method Used	The following weighted-average assumptions used in the Monte Carlo simulation were as follows:
		Year Ended December 31,
		2014				2013				2012
	Expected term (in years)	3				3				3
	Expected volatility	46		%		47		%		54		%
	Risk-free interest rate	0.7		%		0.4		%		0.4		%
	Expected dividends	—				—				—
	Weighted average fair value per share at grant date	$	50.46			$	35.49			$	29.45
2001 Purchase Plan
Weighted Average Assumptions Used for the Fair Value of Options Component of Purchase Plan Granted Estimated at Grant Date	The fair value of the option component of the Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:
		Year Ended December 31,
		2014				2013				2012
	Employee Stock Purchase Plan:
	Expected term (in years)	1.2				1.2				1.2
	Expected volatility	38.8		%		44.9		%		49.7		%
	Risk-free interest rate	0.2		%		0.2		%		0.2		%
	Expected dividends	—				—				—
	Weighted average fair value at grant date	$	17.15			$	11.69			$	11.1
Stock Option
Weighted Average Assumptions Used for the Fair Value of Options Component of Purchase Plan Granted Estimated at Grant Date	Activity for the year ended December 31, 2014, under the stock option plans are set forth below (in thousands, except years and per share amounts):
		Stock Options
		Number of			Weighted				Weighted Average		Aggregate
		Shares			Average				Remaining		Intrinsic
		Underlying			Exercise				Contractual Term		Value
		Stock Options			Price per Share				(in years )
	Outstanding as of December 31, 2013	1,321			16.08
	Granted	—			—
	Exercised	(648	)		16.58
	Cancelled or expired	(5	)		18.32
	Outstanding as of December 31, 2014	668			$	15.57			2.92		$	26,933
	Vested and expected to vest at December 31, 2014	668			$	15.57			2.92		$	26,930
	Exercisable at December 31, 2014	655			$	15.43			2.92		$	26,504
Restricted Stock Units (RSUs)
Summary Of Nonvested Shares	A summary for the year ended December 31, 2014, is as follows (in thousands, except years and per share amounts):
		Shares			Weighted Average Grant Date Fair Value				Weighted		Aggregate
		Underlying  RSUs							Remaining		Intrinsic
									Vesting Period		Value
									(in years)
	Nonvested as of December 31, 2013	2,044			$	31.88
	Granted	981			53.72
	Vested and released	(728	)		30.22
	Forfeited	(173	)		37.59
	Nonvested as of December 31, 2014	2,124			$	42.08			1.33		$	118,727
Market Performance Based Restricted Stock Units
Summary Of Nonvested Shares	The following table summarizes the MSU performance as of December 31, 2014:
		Number of  Shares			Weighted Average Grant Date Fair Value			Weighted  Average		Aggregate
		Underlying MSUs						Remaining		Intrinsic  Value
		(in thousands)						Vesting Period		(in thousands)
								(in years )
	Nonvested as of December 31, 2013	307			31.96
	Granted	244			50.46
	Vested and released	(53	)		22.41
	Nonvested as of December 31, 2014	498			42			1.38		$	27,815

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income before provision for income taxes consisted of the following (in thousands):
		Year ended December 31,
		2014				2013				2012
	Domestic	$	94,784			$	31,993			$	32,341
	Foreign	95,585				61,146				51,955
	Total Income before provision for income taxes	$	190,369			$	93,139			$	84,296
Schedule of Components of Income Tax Expense (Benefit)	The provision for income taxes consisted of the following (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Federal
	Current	$	1,569			$	26			$	—
	Deferred	37,570				24,262				22,382
		39,139				24,288				22,382
	State
	Current	2,162				1,235				438
	Deferred	971				1,158				1,486
		3,133				2,393				1,924
	Foreign
	Current	1,596				3,113				1,173
	Deferred	669				(950		)		126
		2,265				2,163				1,299
	Provision for income taxes	$	44,537			$	28,844			$	25,605
Schedule of Effective Income Tax Rate Reconciliation	The differences between income taxes using the federal statutory income tax rate of 35% and our effective tax rate were as follows:
		Year Ended December 31,
		2014			2013			2012
	U.S. federal statutory income tax rate	35	%		35	%		35	%
	State income taxes, net of federal tax benefit	1.6			2.5			2.4
	Impact of differences in foreign tax rates	(16.4	)		(20.4	)		(20.0	)
	Goodwill Impairment	—			15.3			15.2
	Stock-based compensation	1			0.5			(1.2	)
	Other items not individually material	2.2			(1.9	)		(1.0	)
		23.4	%		31	%		30.4	%
Schedule of Deferred Tax Assets and Liabilities	As of December 31, 2014 and 2013, the significant components of our deferred tax assets and liabilities were (in thousands):
		Year Ended December 31,
		2014				2013
	Deferred tax assets:
	Net operating loss and capital loss carryforwards	$	33,202			$	39,978
	Credit carryforwards	1,446				9,362
	Reserves and accruals	32,888				26,729
	Translation gains	637				48
	Stock-based compensation	11,964				9,100
		80,137				85,217
	Deferred tax liabilities:
	Prepaid expenses	709				557
	Depreciation and amortization	6,878				5,320
		7,587				5,877
	Net deferred tax assets before valuation allowance	72,550				79,340
	Valuation allowance	(32,498		)		(35,108		)
	Net deferred tax assets	$	40,052			$	44,232
Schedule of Unrecognized Tax Benefits Rollforward	The changes in the balance of gross unrecognized tax benefits, which exclude interest and penalties, for fiscal year ended December 31, 2014, 2013, and 2012, is as follows (in thousands):
	Unrecognized tax benefit as of December 31, 2011	$	15,472
	Tax positions related to current year:
	Additions for uncertain tax positions	5,087
	Tax positions related to prior year:
	Additions for uncertain tax positions	80
	Unrecognized tax benefit as of December 31, 2012	20,639
	Tax positions related to current year:
	Additions for uncertain tax positions	6,110
	Tax positions related to prior year:
	Decreases for uncertain tax positions	(81		)
	Unrecognized tax benefit as of December 31, 2013	26,668
	Tax positions related to current year:
	Additions for uncertain tax positions	6,659
	Tax positions related to prior year:
	Decreases for uncertain tax positions	(260		)
	Unrecognized tax benefit as of December 31, 2014	$	33,067

Net_Profit_per_Share_Tables

Net Profit per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
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):
		Year Ended December 31,
		2014		2013		2012
	Numerator:
	Net income	$	145,832	$	64,295	$	58,691
	Denominator:
	Weighted-average common shares outstanding, basic	80,754		80,551		80,529
	Dilutive effect of potential common stock	1,529		2,038		2,511
	Total shares, diluted	82,283		82,589		83,040
	Net income per share, basic	$	1.81	$	0.8	$	0.73
	Net income per share, diluted	$	1.77	$	0.78	$	0.71

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The supplemental cash flow information consists of the following (in thousands):
		Year Ended December 31,
		2014		2013		2012
	Taxes paid	$	5,666	$	4,125	$	2,825
	Non-cash investing and financing activities:
	Fixed assets acquired with accounts payable or accrued liabilities	$	4,899	$	2,308	$	940
	Unclaimed merger consideration liability	$	—	$	—	$	1,575

Segments_and_Geographical_Info1

Segments and Geographical Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [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):
		For the Year Ended December 31,
	Net Revenues	2014		2013		2012
	Clear Aligner
	Invisalign Full Products	$	585,721	$	497,507	$	434,432
	Invisalign Express Products	80,598		72,418		51,486
	Invisalign non-case revenues	46,230		44,724		30,663
	Scanner
	Scanners and Services	49,104		45,557		43,460
	Total net revenues	$	761,653	$	660,206	$	560,041
	Gross Profit
	Clear Aligner	$	562,889	$	484,835	$	405,970
	Scanners and Services	15,554		13,271		10,418
	Total gross profit	$	578,443	$	498,106	$	416,388
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	Net revenues and tangible long-lived assets are presented below by geographic area (in thousands):
		For the Year Ended December 31,
		2014		2013		2012
	Net revenues 1:
	United States	$	532,569	$	491,410	$	427,929
	the Netherlands	156,817		122,494		105,942
	Other international	72,267		46,302		26,170
	Total net revenues	$	761,653	$	660,206	$	560,041
	1	Net revenues are attributed to countries based on location of where revenue is recognized.
		As of December 31,
		2014		2013
	Long-lived assets 2:
	United States	$	76,511	$	61,439
	Mexico	6,229		6,291
	the Netherlands	874		1,630
	Other international	6,511		6,383
	Total long-lived assets	$	90,125	$	75,743
	2	Long-lived assets are attributed to countries based on entity that owns the assets.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	financial_institution
	segment
Significant Accounting Policies [Line Items]
Number of operating segments	2
Restricted cash	$3.80
Original maturity of highly liquid investments included in Cash and cash equivalents	2 years
Foreign currency net loss	3.8
Number of financial instutions used	2
Scanners, Warranty period	1 year
Advertising cost	26.9	26	23.6
Lease term	9 years
Undistributed earnings of foreign subsidiaries	260.9
Medical device tax expense	6.8
Building
Significant Accounting Policies [Line Items]
Property plant and equipment estimated useful lives	20 years
Software Development
Significant Accounting Policies [Line Items]
Property plant and equipment estimated useful lives	10 years
Capitalized computer software development expenses during period	2.6
Minimum
Significant Accounting Policies [Line Items]
Property plant and equipment estimated useful lives	3 years
Estimated useful lives of intangibles	1 year
Maximum
Significant Accounting Policies [Line Items]
Original maturity of highly liquid investments included in Cash and cash equivalents	3 months
Property plant and equipment estimated useful lives	10 years
Estimated useful lives of intangibles	15 years
Noncurrent Assets
Significant Accounting Policies [Line Items]
Restricted cash		4
Other Noncurrent Assets
Significant Accounting Policies [Line Items]
Restricted cash	3.6	4
Prepaid Expenses and Other Current Assets
Significant Accounting Policies [Line Items]
Restricted cash		1.6
Other Current Assets
Significant Accounting Policies [Line Items]
Restricted cash	$0.20

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Out of period adjustment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Net revenues	($761,653)	[1]	($660,206)	[1]	($560,041)	[1]
Operating expenses	384,867		403,894		330,796
Provision for income taxes	44,537		28,844		25,605
Net income	145,832		64,295		58,691
Restatement Adjustment [Member]
Net revenues			1,700
Operating expenses			-700
Provision for income taxes			500
Net income			1,900
Out Of Period Correction [Member]
Provision for income taxes	$1,800
[1]	2B Long-lived assets are attributed to countries based on entity that owns the assets.

Marketable_Securities_and_Fair2

Marketable Securities and Fair Value Measurements - Short-term and Long-term Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$254,843,000	$126,992,000
Gross Unrealized Gains	61,000	55,000
Gross Unrealized Losses	-117,000	-7,000
Fair Value	254,787,000	127,040,000
Short-term Investments | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,998,000	54,318,000
Gross Unrealized Gains	0	10,000
Gross Unrealized Losses	0	0
Fair Value	33,998,000	54,328,000
Short-term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	152,055,000	29,079,000
Gross Unrealized Gains	27,000	10,000
Gross Unrealized Losses	-116,000	-4,000
Fair Value	151,966,000	29,085,000
Short-term Investments | U.S. dollar dominated foreign corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	901,000	13,959,000
Gross Unrealized Gains	0	12,000
Gross Unrealized Losses	0	0
Fair Value	901,000	13,971,000
Short-term Investments | Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,147,000	7,006,000
Gross Unrealized Gains	13,000	11,000
Gross Unrealized Losses	0	-3,000
Fair Value	9,160,000	7,014,000
Short-term Investments | U.S. government agency bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41,574,000	16,693,000
Gross Unrealized Gains	14,000	10,000
Gross Unrealized Losses	-1,000	0
Fair Value	41,587,000	16,703,000
Short-term Investments | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,770,000	5,937,000
Gross Unrealized Gains	7,000	2,000
Gross Unrealized Losses	0	0
Fair Value	15,777,000	5,939,000
Short-term Investments | Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,398,000
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	1,398,000
Long Term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	148,030,000	101,973,000
Gross Unrealized Gains	28,000	62,000
Gross Unrealized Losses	-166,000	-57,000
Fair Value	147,892,000	101,978,000
Long Term Investments | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	57,195,000	23,308,000
Gross Unrealized Gains	6,000	14,000
Gross Unrealized Losses	-112,000	-9,000
Fair Value	57,089,000	23,313,000
Long Term Investments | U.S. dollar dominated foreign corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	523,000	19,485,000
Gross Unrealized Gains	0	27,000
Gross Unrealized Losses	-2,000	-17,000
Fair Value	521,000	19,495,000
Long Term Investments | Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,552,000	8,326,000
Gross Unrealized Gains	5,000	13,000
Gross Unrealized Losses	-6,000	-8,000
Fair Value	9,551,000	8,331,000
Long Term Investments | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,713,000	5,800,000
Gross Unrealized Gains	0	4,000
Gross Unrealized Losses	-12,000	-2,000
Fair Value	11,701,000	5,802,000
Long Term Investments | US Government Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	48,233,000	38,138,000
Gross Unrealized Gains	12,000	1,000
Gross Unrealized Losses	-28,000	-21,000
Fair Value	48,217,000	38,118,000
Long Term Investments | U.S. Government Treasury Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,814,000	6,916,000
Gross Unrealized Gains	5,000	3,000
Gross Unrealized Losses	-6,000	0
Fair Value	$20,813,000	$6,919,000

Marketable_Securities_and_Fair3

Marketable Securities and Fair Value Measurements - Marketable Securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, All Other Investments [Abstract]
One year or less	$254,787	$127,040
One year through two years	147,892	101,978
Marketable Securities	$402,679	$229,018

Marketable_Securities_and_Fair4

Marketable Securities and Fair Value Measurements - Fair Value Measured On A Recurring Basis (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$254,787,000	$127,040,000
Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	147,892,000	101,978,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	509,514,000	390,149,000
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	117,376,000	150,459,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets measured at fair value	392,138,000	239,690,000
Money market funds | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	80,786,000	143,540,000
Money market funds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	80,786,000	143,540,000
Money market funds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	0	0
Commercial paper | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	33,998,000	54,328,000
Commercial paper | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	21,997,000	15,398,000
Commercial paper | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	33,998,000	54,328,000
Commercial paper | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	0	0
Commercial paper | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Commercial paper | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	21,997,000	15,398,000
Commercial paper | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	33,998,000	54,328,000
Corporate bonds | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	1,745,000
Corporate bonds | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	151,966,000	29,085,000
Corporate bonds | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	57,089,000	23,313,000
Corporate bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	0
Corporate bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Corporate bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market funds	1,745,000
Corporate bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	151,966,000	29,085,000
Corporate bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	57,089,000	23,313,000
U.S. dollar dominated foreign corporate bonds | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	901,000	13,971,000
U.S. dollar dominated foreign corporate bonds | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	521,000	19,495,000
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	901,000	13,971,000
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	521,000	19,495,000
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	901,000	13,971,000
U.S. dollar dominated foreign corporate bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	521,000	19,495,000
U.S. government agency bonds | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	41,587,000	16,703,000
U.S. government agency bonds | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	41,587,000	16,703,000
U.S. government agency bonds | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	48,217,000	38,118,000
U.S. government agency bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
U.S. government agency bonds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
U.S. government agency bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	41,587,000	16,703,000
U.S. government agency bonds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	48,217,000	38,118,000
Israeli funds | Fair Value, Measurements, Recurring | Other assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	2,307,000	2,193,000
Israeli funds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	0	0
Israeli funds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Other assets	2,307,000	2,193,000
Municipal Securities [Member] | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,160,000	7,014,000
Municipal Securities [Member] | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,551,000	8,331,000
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,160,000	7,014,000
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,551,000	8,331,000
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,160,000	7,014,000
Municipal Securities [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	9,551,000	8,331,000
Asset-backed Securities [Member] | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	15,777,000	5,939,000
Asset-backed Securities [Member] | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,701,000	5,802,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,398,000	5,939,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,701,000	5,802,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0	0
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	1,398,000	5,939,000
Asset-backed Securities [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	11,701,000	5,802,000
U.S. Government Treasury Bonds [Member] | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20,813,000	6,919,000
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	15,777,000
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20,813,000	6,919,000
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	15,777,000
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	20,813,000	6,919,000
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	0
U.S. Government Treasury Bonds [Member] | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Long Term Investments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments	$0	$0

Marketable_Securities_and_Fair5

Marketable Securities and Fair Value Measurements - Narrative (Details) (USD $)	12 Months Ended			3 Months Ended			6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Original maturity of highly liquid investments included in Cash and cash equivalents	2 years
Weighted average maturity	10 months	11 months
Impairment of long lived assets	$0	$26,320	$0
Impairment of goodwill	0	40,693	36,591
Scanners and CAD/CAM Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long lived assets				7,000
Impairment of goodwill		$40,693	$36,600	$40,700	$11,900	$24,700	$36,600

Balance_Sheet_Components_Inven

Balance Sheet Components - Inventories (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]
Raw materials	$8,143	$5,172
Work in process	2,970	4,241
Finished goods	4,815	4,555
Inventories	$15,928	$13,968

Balance_Sheet_Components_Prope

Balance Sheet Components - Property and Equipment (Detail) (USD $)	12 Months Ended			1 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Mar. 31, 2013
Property, Plant and Equipment, Net [Abstract]
Property and equipment	$197,927,000	$181,249,000
Less: Accumulated depreciation and amortization	-107,802,000	-105,506,000
Property, plant and equipment, net	90,125,000	75,743,000
Impairment of property and equipment	0	26,320,000	0
Depreciation and amortization	14,800,000	13,900,000	13,400,000
Scanners and CAD/CAM Services
Property, Plant and Equipment, Net [Abstract]
Asset impairment charges				26,300,000
Impairment of property and equipment					7,000,000
Software Development
Property, Plant and Equipment, Net [Abstract]
Capitalized computer software development expenses during period	2,600,000
Clinical and manufacturing equipment
Property, Plant and Equipment, Net [Abstract]
Property and equipment	107,707,000	104,373,000
Computer hardware
Property, Plant and Equipment, Net [Abstract]
Property and equipment	24,092,000	24,851,000
Computer software
Property, Plant and Equipment, Net [Abstract]
Property and equipment	22,044,000	21,286,000
Furniture and fixtures
Property, Plant and Equipment, Net [Abstract]
Property and equipment	7,386,000	7,275,000
Leasehold improvements
Property, Plant and Equipment, Net [Abstract]
Property and equipment	15,358,000	14,996,000
Building
Property, Plant and Equipment, Net [Abstract]
Property and equipment	1,868,000	1,868,000
Land
Property, Plant and Equipment, Net [Abstract]
Property and equipment	1,162,000	1,162,000
Construction in progress
Property, Plant and Equipment, Net [Abstract]
Property and equipment	$18,310,000	$5,438,000

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]
Accrued payroll and benefits	$44,610	$43,029
Accrued sales rebate	11,110	10,100
Accrued sales tax and value added tax	5,456	6,215
Accrued sales and marketing expenses	5,979	3,893
Accrued warranty	3,148	3,104
Accrued accounts payable	5,736	4,053
Accrued professional fees	2,494	1,892
Accrued income taxes	2,027	1,205
Other	7,320	6,854
Total current accrued liabilities	$87,880	$80,345

Balance_Sheet_Components_Warra

Balance Sheet Components - Warranty Accrual Activity (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$3,104	$4,050
Charged to cost of revenues	1,990	2,850
Actual warranty expenditures	-1,946	-3,796
Balance at end of period	$3,148	$3,104

Balance_Sheet_Components_Addit

Balance Sheet Components - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Scanners, Warranty period	1 year

Business_Combinations_Addition

Business Combinations - Additional Information (Detail) (USD $)	12 Months Ended			3 Months Ended			6 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012	Apr. 29, 2011	Apr. 30, 2013
Business Acquisition [Line Items]
Acquisition, net of cash acquired	$0	$7,652,000	$0
Goodwill	61,369,000	61,623,000	99,236,000		99,236,000		99,236,000
Impairment of goodwill	0	40,693,000	36,591,000
Gross profit	578,443,000	498,106,000	416,388,000
Scanners and CAD/CAM Services
Business Acquisition [Line Items]
Goodwill	0	0	40,693,000		40,693,000		40,693,000
Impairment of goodwill		40,693,000	36,600,000	40,700,000	11,900,000	24,700,000	36,600,000
Gross profit	15,554,000	13,271,000	10,418,000
Clear Aligner
Business Acquisition [Line Items]
Goodwill	61,369,000	61,623,000	58,543,000		58,543,000		58,543,000
Impairment of goodwill		0
Gross profit	562,889,000	484,835,000	405,970,000
Cadent [Member]
Business Acquisition [Line Items]
Acquisition, net of cash acquired								187,600,000
Goodwill								135,300,000
Cadent [Member] | Scanners and CAD/CAM Services
Business Acquisition [Line Items]
Goodwill								77,300,000
Cadent [Member] | Clear Aligner
Business Acquisition [Line Items]
Goodwill								58,000,000
ICA Holdings Pty Limited [Member]
Business Acquisition [Line Items]
Acquisition, net of cash acquired									8,600,000
Goodwill									3,600,000
Assets acquired									7,400,000
Liabilities assumed									$2,400,000

Business_Combinations_Summary_

Business Combinations - Summary of Allocation of the Preliminary Purchase Price (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Goodwill	$61,369	$61,623	$99,236

Business_Combinations_Summary_1

Business Combinations - Summary of Allocation of the Preliminary Purchase Price Parenthetical (Detail)	0 Months Ended	12 Months Ended
	Apr. 29, 2011	Dec. 31, 2014	Dec. 31, 2013
Trademarks
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles		15 years	15 years
Existing technology
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles	13 years	13 years	13 years
Customer Relationships [Member]
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles	11 years	11 years	11 years
Minimum
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles		1 year
Minimum | Trademarks
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles	1 year
Maximum
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles		15 years
Maximum | Trademarks
Schedule of Business Acquisitions, Purchase Price Allocation [Line Items]
Estimated useful lives of intangibles	15 years

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Change in the Carrying Value of Goodwill (Detail) (USD $)	3 Months Ended			6 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Goodwill [Line Items]
Goodwill, Translation Adjustments					($254)	($478)	[1]
Goodwill [Roll Forward]
Balance, Beginning Balance	99,236				61,623	99,236
Adjustment to goodwill					0	3,558
Impairment of goodwill					0	-40,693		-36,591
Balance, Ending Balance		99,236		99,236	61,369	61,623		99,236
Clear Aligner
Goodwill [Line Items]
Goodwill, Translation Adjustments					-254	-478	[1]
Goodwill [Roll Forward]
Balance, Beginning Balance	58,543				61,623	58,543
Adjustment to goodwill					0	3,558
Impairment of goodwill						0
Balance, Ending Balance					61,369	61,623
Scanners and CAD/CAM Services
Goodwill [Line Items]
Goodwill, Translation Adjustments					0	0	[1]
Goodwill [Roll Forward]
Balance, Beginning Balance	40,693				0	40,693
Adjustment to goodwill					0	0
Impairment of goodwill	-40,700	-11,900	-24,700	-36,600		-40,693		-36,600
Balance, Ending Balance		$40,693		$40,693	$0	$0		$40,693
[1]	The adjustments to goodwill were a result of foreign currency translation.

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Intangible Assets as a Direct Result from the Cadent Acquisition (Detail) (USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Apr. 29, 2011	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount as of December 31, 2012		$53,485	$53,485
Accumulated Amortization		-13,540	-10,488
Impairment Charge		-19,258	-19,258
Total		20,687	23,739
Trademarks
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangibles		15 years	15 years
Gross Carrying Amount as of December 31, 2012		7,100	7,100
Accumulated Amortization		-1,354	-1,100
Impairment Charge		-4,179	-4,179
Total		1,567	1,821
Existing technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangibles	13 years	13 years	13 years
Gross Carrying Amount as of December 31, 2012		12,600	12,600
Accumulated Amortization		-3,015	-2,236
Impairment Charge		-4,328	-4,328
Total		5,257	6,036
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangibles	11 years	11 years	11 years
Gross Carrying Amount as of December 31, 2012		33,500	33,500
Accumulated Amortization		-9,095	-7,112
Impairment Charge		-10,751	-10,751
Total		13,654	15,637
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives of intangibles		8 years	8 years
Gross Carrying Amount as of December 31, 2012		285	285
Accumulated Amortization		-76	-40
Impairment Charge		0	0
Total		$209	$245

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Total Estimated Annual Future Amortization Expense for the Acquired Intangible Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2014	$2,600
2015	2,600
2016	2,600
2017	2,600
2018	2,600
Thereafter	7,687
Total	$20,687	$23,739

Goodwill_and_Intangible_Assets5

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	3 Months Ended			6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012
Goodwill [Line Items]
Impairment of goodwill	$0	$40,693,000	$36,591,000
Goodwill	61,369,000	61,623,000	99,236,000			99,236,000		99,236,000
Impairment of long lived assets	0	26,320,000	0
Scanners and CAD/CAM Services
Goodwill [Line Items]
Impairment of goodwill		40,693,000	36,600,000		40,700,000	11,900,000	24,700,000	36,600,000
Goodwill	0	0	40,693,000			40,693,000		40,693,000
Asset impairment charges				26,300,000
Impairment of intangible assets				19,300,000
Impairment of long lived assets					$7,000,000

Credit_Facilities_Additional_I

Credit Facilities - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Mar. 22, 2013
Line of Credit Facility [Line Items]
Line of credit, available borrowings		$50,000,000
Current borrowing capacity		10,000,000
Minimum unrestricted cash balance requirement	50,000,000
Interest rate on borrowings at LIBOR plus, minimum	1.75%
Interest rate on borrowings at LIBOR plus, maximum	1.75%
Line of credit, amount outstanding	$0

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Total rent expense	$7.60	$7.30	$6.90

Commitments_and_Contingencies_2

Commitments and Contingencies - Minimum Future Lease Payments for Non-Cancelable Leases (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2014	$9,130
2015	8,293
2016	4,659
2017	1,545
2018	209
Thereafter	210
Total minimum lease payments	$24,046

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 28, 2005	16-May-13
	purchase_period
Stockholders Equity Note [Line Items]
Preferred stock, par value (usd per share)	$0.00	$0.00
Total intrinsic value of stock options exercised	$24,500,000	$46,700,000	$50,900,000
Fair value of stock options vested	700,000	3,700,000	5,000,000
Tax effect from exercised stock options	1,900,000
Employees' taxes paid upon the vesting of restricted stock units	-7,608,000	-4,363,000	-2,106,000
Employee Stock Purchase Plan, Duration Of Offering Period	24 months
Number of offering periods	4
Stock-based compensation expense	39,823,000	26,438,000	21,483,000
Stockholder Rights Plan
Stockholders Equity Note [Line Items]
Preferred stock purchase right, number of rights declared for each outstanding share of our common stock	1
Dividend distribution, date of record	22-Nov-05
Preferred stock, par value (usd per share)	$0.00
Preferred stock purchase right, exercise price (usd per share)	$37
Number of shares called by each right (shares)	0.001
Preferred stock purchase right, minimum ownership percentage that should be acquired or intended to be acquired to trigger exercise	15.00%
Ratio of common stock to purchase price	2
Preferred stock purchase right, expiration Date	NovemberB 22, 2015
Amended And Restated 2005 Stock Incentive Plan
Stockholders Equity Note [Line Items]
Shares reserved for issuance	7,325,130
2001 Purchase Plan
Stockholders Equity Note [Line Items]
Employee stock purchase plan, purchase price as percentage of fair market value of common stock	85.00%
Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Vested rand released in period, Total intrinsic value	38,900,000	20,300,000	12,500,000
Vested in period, Fair value	22,000,000	13,200,000	7,800,000
Total unamortized compensation cost	32,100,000
Weighted average period of total unamortized cost	2 years 2 months 12 days
Restricted stock units, shares vested and released (shares)	727,679
Restricted stock units, shares withheld for tax payments	114,468
Restricted stock units, net issuance	613,211
Stock Options | Incentive Plan 2005
Stockholders Equity Note [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	25% vesting one year from the date of grant and 1/48th each month thereafter
Stock incentive plan, term	7 years
Stock incentive plan, vesting period	4 years
Market Performance Based Restricted Stock Units
Stockholders Equity Note [Line Items]
Vested rand released in period, Total intrinsic value	2,900,000
Vested in period, Fair value	1,200,000
Total unamortized compensation cost	6,200,000
Weighted average period of total unamortized cost	1 year 4 months 24 days
Restricted stock units, shares vested and released (shares)	52,575
Restricted stock units, shares withheld for tax payments	25,214
Restricted stock units, net issuance	27,361
Market Performance Based Restricted Stock Units | Minimum
Stockholders Equity Note [Line Items]
Stock incentive plan, vesting period	2 years
Market Performance Based Restricted Stock Units | Maximum
Stockholders Equity Note [Line Items]
Stock incentive plan, vesting period	3 years
Percentage of market-performance based restricted stock units eligible to vest over the vesting period	150.00%
Employee Stock Incentive Plan 2005 [Member]
Stockholders Equity Note [Line Items]
Number of shares available for grant (shares)					23,283,379
Shares Transferred From 2001 Stock Incentive Plan
Stockholders Equity Note [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period				5,000,000
Employee Stock Purchase Plan 2010
Stockholders Equity Note [Line Items]
Employee stock purchase plan, shares issued	247,343	288,675	336,382
Weighted average exercise price (usd per share)	$29.24	$21.96	$17.98
Number of shares available for grant (shares)	1,363,827
Employee Stock Purchase Plan 2010 | Maximum
Stockholders Equity Note [Line Items]
Maximum number of shares available	2,400,000
Employee Stock Purchase Plan
Stockholders Equity Note [Line Items]
Total unamortized compensation cost	800,000
Weighted average period of total unamortized cost	3 months 18 days
Stock-based compensation expense	$2,600,000	$3,400,000	$2,000,000
Annual Vesting | Stock Options | Incentive Plan 2005
Stockholders Equity Note [Line Items]
Stock incentive plan, vesting percentage	25.00%
Monthly Vesting | Stock Options | Incentive Plan 2005
Stockholders Equity Note [Line Items]
Stock incentive plan, vesting percentage	2.08%

Stockholders_Equity_StockBased

Stockholders' Equity - Stock-Based Awards and Employee Stock Purchases (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$39,823	$26,438	$21,483
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,616	2,565	1,843
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	11,646	7,093	5,581
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	17,979	13,261	10,361
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$6,582	$3,519	$3,698

Stockholders_Equity_Activity_U

Stockholders' Equity - Activity Under Stock Option Plans (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014
Number of Shares Underlying Stock Options
Outstanding beginning balance (shares)	1,321
Granted (shares)	0
Exercised (shares)	-648
Cancelled or expired (shares)	-5
Outstanding ending balance (shares)	668
Vested and expected to vest at December 31, 2013 (shares)	668
Exercisable at December 31, 2013 (shares)	655
Weighted Average Exercise Price per Share
Outstanding beginning balance (usd per share)	$16.08
Granted (usd per share)	$0
Exercised (usd per share)	$16.58
Cancelled or expired (usd per share)	$18.32
Outstanding ending balance (usd per share)	$15.57
Vested and expected to vest at December 31, 2013 (usd per share)	$15.57
Exercisable at December 31, 2013 (usd per share)	$15.43
Weighted Average Remaining Contractual Term (in years)
Outstanding as of December 31, 2014	2 years 11 months 1 day
Vested and expected to vest at December 31, 2014	2 years 11 months 1 day
Exercisable at December 31, 2014	2 years 11 months 1 day
Aggregate Intrinsic Value
Outstanding as of December 31, 2014	$26,933
Vested and expected to vest at December 31, 2014	26,930
Exercisable at December 31, 2014	$26,504

Stockholders_Equity_Weighted_A

Stockholders' Equity - Weighted Average Assumptions Used for the Fair Value of Stock Options Granted Estimated at Grant Date Using Black-Scholes Option Pricing Model (Detail) (Stock Options)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	0 years	0 years

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Nonvested Shares (Detail) (Restricted Stock Units (RSUs), USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
Restricted Stock Units (RSUs)
Shares Underlying RSUs
Nonvested beginning balance (shares)	2,044,000
Granted (shares)	981,000
Vested and released (shares)	-727,679
Forfeited (shares)	-173,000
Nonvested ending balance (shares)	2,124,000
Nonvested, beginning balance (usd per share)	$31.88
Granted (usd per share)	$53.72
Vested and released (usd per share)	$30.22
Forfeited (usd per share)	$37.59
Nonvested, ending balance (usd per share)	$42.08
Weighted Remaining Vesting Period (in years)
Nonvested as of December 31, 2014	1 year 3 months 29 days
Aggregate Intrinsic Value
Nonvested as of December 31, 2014	$118,727

Stockholders_Equity_Summary_of1

Stockholders' Equity - Summary of MSU Performance (Detail) (Market Performance Based Restricted Stock Units, USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Market Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$42	$31.96
Number of Shares
Nonvested beginning balance (shares)	307,000
Granted (shares)	244,000
Granted (usd per share)	$50.46	$35.49	$29.45
Vested and released (shares)	-52,575
Nonvested ending balance (shares)	498,000	307,000
Weighted Average Remaining Contractual Term
Nonvested	1 year 4 months 17 days
Aggregate Intrinsic Value
Nonvested	$27,815
Sharebased Compensation Arrangement By Sharebased Payment Award Equity Instruments Other Than Options Vested And Released In Period Weighted Average Grant Date Fair Value	$22.41

Stockholders_Equity_WeightedAv

Stockholders' Equity - Weighted-Average Assumptions Used in the Monte Carlo Simulation (Detail) (Market Performance Based Restricted Stock Units, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Market Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	3 years	3 years	3 years
Expected volatility	46.00%	47.00%	54.00%
Risk-free interest rate	0.70%	0.40%	0.40%
Expected dividends	0.00%	0.00%	0.00%
Weighted average fair value per share at grant date (usd per share)	$50.46	$35.49	$29.45

Stockholders_Equity_Weighted_A1

Stockholders' Equity - Weighted Average Assumptions Used for the Fair Value of the Option Component of the Purchase Plan Shares Estimated at Grant Date Using Black-Scholes Option Pricing Model (Detail) (Employee Stock Purchase Plan, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	1 year 2 months 12 days	1 year 2 months 12 days	1 year 2 months 12 days
Expected volatility	38.80%	44.90%	49.70%
Risk-free interest rate	0.20%	0.20%	0.20%
Expected dividends	0.00%	0.00%	0.00%
Weighted average fair value at grant date (usd per share)	$17.15	$11.69	$11.10

Common_Stock_Repurchase_Progra1

Common Stock Repurchase Program - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended				3 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 29, 2014	Apr. 29, 2014	Apr. 28, 2014	Apr. 23, 2014	Jul. 29, 2014	Jan. 31, 2015	Oct. 27, 2011
Share Repurchases [Line Items]
Common stock repurchased and retired	$98,233,000	$95,107,000	$47,203,000
Additional Paid-in Capital
Share Repurchases [Line Items]
Common stock repurchased and retired	17,804,000	24,528,000	15,399,000
Retained Earnings
Share Repurchases [Line Items]
Common stock repurchased and retired	80,429,000	70,579,000	31,804,000
October 2011 Stock Repurchase Program
Share Repurchases [Line Items]
Repurchase of common stock, common stock authorized										150,000,000
Common stock repurchased and retired (shares)		2,700,000	1,700,000
Common stock repurchased (in dollars per share)		$34.95	$27.28
Common stock repurchased and retired		95,107,000	47,200,000
October 2011 Stock Repurchase Program | Additional Paid-in Capital
Share Repurchases [Line Items]
Repurchase of common stock, aggregate purchase price - Increase/(Decrease) In Equity		-24,500,000	-15,400,000
October 2011 Stock Repurchase Program | Retained Earnings
Share Repurchases [Line Items]
Repurchase of common stock, aggregate purchase price - Increase/(Decrease) In Equity		-70,600,000	-31,800,000
April 2014 Stock Repurchase Program
Share Repurchases [Line Items]
Repurchase of common stock, common stock authorized							300,000,000
Common stock repurchased and retired (shares)	600,000
Common stock repurchased (in dollars per share)	$50.93
Common stock repurchased and retired	28,200,000
Authorized stock repurchase amount over next twelve months							100,000,000
Accelerated share repurchase agreement amount						70,000,000
Accelerated share repurchase amount					70,000,000
Accelerated share repurchase (in shares)				400,000	1,000,000			1,400,000
Accelerated share repurchases price per share (in dollars per share)				$51.46
Remaining authorized repurchase amount	201,800,000
April 2014 Stock Repurchase Program | Subsequent Event
Share Repurchases [Line Items]
Common stock repurchased and retired									1,800,000
Additional authorized repurchase amount									$100,000,000

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2009
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Accrued severance funds liability	$2.50	$2.40
Defined Contribution Pension Plan 401k
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Employer matching contribution as percentage of employee's salary deferral contributions				50.00%
Employer matching contribution as percentage of employee's eligible compensation				6.00%
Employer contributions amount	$2.20	$2.10	$1.90

Income_Taxes_Domestic_and_Fore

Income Taxes - Domestic and Foreign Components of Income (loss) Before Provision for Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic	$94,784	$31,993	$32,341
Foreign	95,585	61,146	51,955
Net income before provision for income taxes	$190,369	$93,139	$84,296

Income_Taxes_Income_Taxes_Prov

Income Taxes Income Taxes - Provision for (Benefit from) Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Federal
Current	$1,569	$26	$0
Deferred	37,570	24,262	22,382
Total federal income tax expense	39,139	24,288	22,382
State
Current	2,162	1,235	438
Deferred	971	1,158	1,486
Total state tax expense	3,133	2,393	1,924
Foreign
Current	1,596	3,113	1,173
Deferred	669	-950	126
Total foreign tax expense	2,265	2,163	1,299
Provision for income taxes	$44,537	$28,844	$25,605

Income_Taxes_Differences_Betwe

Income Taxes - Differences Between Income Taxes Using Federal Statutory Income Tax Rate and Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit	1.60%	2.50%	2.40%
Impact of differences in foreign tax rates	-16.40%	-20.40%	-20.00%
Goodwill Impairment	0.00%	15.30%	15.20%
Amortization of stock-based compensation	1.00%	0.50%	-1.20%
Other items not individually material	2.20%	-1.90%	-1.00%
Effective Income Tax Rate, Continuing Operations, Total	23.40%	31.00%	30.40%

Income_Taxes_Income_Taxes_Defe

Income Taxes Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Net operating loss and capital loss carryforwards	$33,202	$39,978
Credit carryforwards	1,446	9,362
Reserves and accruals	32,888	26,729
Translation gains	637	48
Stock-based compensation	11,964	9,100
Total deferred tax assets, gross	80,137	85,217
Deferred tax liabilities:
Prepaid expenses	709	557
Depreciation and amortization	6,878	5,320
Total deferred tax liabilities, gross	7,587	5,877
Net deferred tax assets before valuation allowance	72,550	79,340
Valuation allowance	-32,498	-35,108
Net deferred tax assets	$40,052	$44,232

Income_Taxes_Rollforward_of_To

Income Taxes - Rollforward of Total Gross Unrecognized Tax Benefit (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit as of beginning of period	$26,668	$20,639	$15,472
Tax positions related to current year, additions for uncertain tax positions	6,659	6,110	5,087
Tax positions related to prior year, additions for uncertain tax positions		-81	80
Decreases for uncertain tax positions	-260
Unrecognized tax benefit as of end of period	$33,067	$26,668	$20,639

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2009	Dec. 31, 2011
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount	$1,800,000
Undistributed earnings of foreign subsidiaries	260,900,000
Deferred tax assets, valuation allowance	32,498,000	35,108,000
Change in valuation allowance	2,600,000
Tax benefits associated with the exercise of employee stock options and utilization of net operating loss carryover applicable to stock options	21,400,000	27,100,000	17,200,000
Increase in unrecognized tax benefits	6,400,000
Unrecognized tax benefits	33,067,000	26,668,000	20,639,000		15,472,000
Acquisition Related Assets And Foreign Net Operating Loss Carryforwards [Member]
Income Taxes [Line Items]
Change in valuation allowance	1,800,000
Lapse In Statute Of Limitations [Member]
Income Taxes [Line Items]
Change in valuation allowance	800,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards	37,300,000
State and Local Jurisdiction | Research
Income Taxes [Line Items]
Research credit carryforward	3,800,000
Foreign Country
Income Taxes [Line Items]
Net operating loss carryforwards	125,500,000
Foreign Country | Costa Rica
Income Taxes [Line Items]
Tax incentives, period				12 years
Tax incentives, corporate income tax rate that would apply absent the incentives	30.00%
Tax incentives, reduction in income taxes	32,500,000	27,700,000	21,800,000
Tax benefit of tax holiday on net income per share (diluted) (usd per share)	$0.40	$0.34	$0.26
Stock Options
Income Taxes [Line Items]
Net operating loss carryforwards	$23,800,000

Net_Profit_per_Share_Computati

Net Profit per Share - Computation of Basic and Diluted Net Profit Per Share Attributable to Common Stock (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income	$145,832	$64,295	$58,691
Denominator:
Weighted-average common shares outstanding, basic (shares)	80,754	80,551	80,529
Dilutive effect of potential common stock (shares)	1,529	2,038	2,511
Total shares, diluted (shares)	82,283	82,589	83,040
Net income per share, basic (usd per share)	$1.81	$0.80	$0.73
Net income per share, diluted (usd per share)	$1.77	$0.78	$0.71

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Information [Abstract]
Taxes paid	$5,666	$4,125	$2,825
Non-cash investing and financing activities:
Fixed assets acquired with accounts payable or accrued liabilities	4,899	2,308	940
Unclaimed merger consideration liability	$0	$0	$1,575

Segments_and_Geographical_Info2

Segments and Geographical Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segments_and_Geographical_Info3

Segments and Geographical Information Segments and Geographical Information - (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenue	$761,653	[1]	$660,206	[1]	$560,041	[1]
Gross profit	578,443		498,106		416,388
Invisalign Full [Member]
Segment Reporting Information [Line Items]
Revenue	585,721		497,507		434,432
Invisalign Express/Lite [Member]
Segment Reporting Information [Line Items]
Revenue	80,598		72,418		51,486
Invisalign Non-Case Revenues [Member]
Segment Reporting Information [Line Items]
Revenue	46,230		44,724		30,663
Scanners [Member]
Segment Reporting Information [Line Items]
Revenue	49,104		45,557		43,460
Clear Aligner
Segment Reporting Information [Line Items]
Gross profit	562,889		484,835		405,970
Scanners and CAD/CAM Services
Segment Reporting Information [Line Items]
Gross profit	$15,554		$13,271		$10,418
[1]	2B Long-lived assets are attributed to countries based on entity that owns the assets.

Segments_and_Geographical_Info4

Segments and Geographical Information - Net Revenues by Geographic Area (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Net revenues	$761,653	[1]	$660,206	[1]	$560,041	[1]
United States
Segment Reporting Information [Line Items]
Net revenues	532,569	[1]	491,410	[1]	427,929	[1]
the Netherlands
Segment Reporting Information [Line Items]
Net revenues	156,817	[1]	122,494	[1]	105,942	[1]
Other international
Segment Reporting Information [Line Items]
Net revenues	$72,267	[1]	$46,302	[1]	$26,170	[1]
[1]	2B Long-lived assets are attributed to countries based on entity that owns the assets.

Segments_and_Geographical_Info5

Segments and Geographical Information - Long-Lived Assets by Geographic Area (Detail) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Segment Reporting Information [Line Items]
Long-lived assets	$90,125	[1]	$75,743	[1]
United States
Segment Reporting Information [Line Items]
Long-lived assets	76,511	[1]	61,439	[1]
Mexico
Segment Reporting Information [Line Items]
Long-lived assets	6,229	[1]	6,291	[1]
the Netherlands
Segment Reporting Information [Line Items]
Long-lived assets	874	[1]	1,630	[1]
Other international
Segment Reporting Information [Line Items]
Long-lived assets	$6,511	[1]	$6,383	[1]
[1]	Long-lived assets are attributed to countries based on entity that owns the assets.

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts and Reserves (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2009
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$1,733	$3,167			$1,500
Additions (reductions) to Costs and Expenses	6,563	2,116		4,417
Write offs	-6,733	-3,550		-2,735
Charged to Other Accounts	0	0		0
Reclassification from Other Accounts	0	0		-15
Balance at End of Period	1,563	1,733		3,167	1,500
Allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	35,108	27,056			20,224
Additions (reductions) to Costs and Expenses	-1,793	9,806		8,507
Write offs	-817	-1,754		-1,675
Charged to Other Accounts		0	[1]	0
Reclassification from Other Accounts		0		0
Balance at End of Period	$32,498	$35,108		$27,056	$20,224
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