Maturity Threshold Of Investments Classified To Cash Equivalents

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Revenue, Percentage

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Sales Return Coverage Period

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Working Capital

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- Definition

Amount of liability recognized arising from contingent consideration in a business combination.

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-Name Accounting Standards Codification

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-Section 25

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Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

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-Name Accounting Standards Codification

-Glossary Cash

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-Glossary Cash Equivalents

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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-Name Accounting Standards Codification

-Topic 740

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-Paragraph 2

-Subparagraph (c)

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Unrecognized cost of unvested share-based compensation awards.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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-Glossary Income Tax Expense (or Benefit)

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Expiration date of the tax credit carryforward, in CCYY-MM-DD format.

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Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 06, 2012
Organization And Summary Of Significant Accounting Policies [Line Items]
Letters of Credit Outstanding, Amount	$ 0.7				$ 0.7				$ 0.7	$ 0.7
Maturity Threshold Of Investments Classified To Cash Equivalents									90
Accumulated deficit	497.8				475.4				497.8	475.4
Cash, cash equivalents and short-term investments	83.6								83.6
Restricted cash	1.0				1.0				1.0	1.0
Working capital	105.3dxcm_WorkingCapital								105.3dxcm_WorkingCapital
Unrecognized compensation cost	105.1								105.1
Money back guarantee period (days)									30 days
Revenues	84.3us-gaap_Revenues	69.0us-gaap_Revenues	58.8us-gaap_Revenues	47.1us-gaap_Revenues	51.7us-gaap_Revenues	42.9us-gaap_Revenues	35.8us-gaap_Revenues	29.6us-gaap_Revenues
Valuation allowance amount	169.0				164.7				169.0	164.7
Net tax benefit (expense)									(0.1)us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	1.3us-gaap_IncomeTaxExpenseBenefit
Tax Credit Carryforward, Expiration Date									Jan. 01, 2020
Fair value of contingent consideration												2.2
Customer [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Concentration Risk, Percentage									10.00%
Byram [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Revenues									46.1	24.3	9.6
Concentration Risk, Percentage									18.00%	15.00%	9.00%
Edgepark [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Revenues									$ 28.1	$ 23.1	$ 14.8
Concentration Risk, Percentage									11.00%	14.00%	15.00%
Computer Equipment [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life									3 years
Machinery and Equipment [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life									4 years
Furniture and Fixtures [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life									5 years
International [Member]
Organization And Summary Of Significant Accounting Policies [Line Items]
Revenue, Percentage									14.00%	10.00%	10.00%