XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Measurements (Details) - USD ($) | Sep. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2017
--- | --- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Cash equivalents | $ 215,400,000 | $ 344,600,000 |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 258,500,000 | 107,100,000 |
Fair value, assets, level 1 to level 2 transfers | 0 |  | $ 0
Fair value, assets, level 3 transfers | 0 |  | $ 0
Fair value of outstanding notes | 618,800,000 | 381,300,000 |
Fair Value, Inputs, Level 1 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Cash equivalents | 177,600,000 | 306,600,000 |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
Fair Value, Inputs, Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Cash equivalents | 37,800,000 | 38,000,000 |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 258,500,000 | 107,100,000 |
Fair value of outstanding notes | 618,800,000 |  |
Fair Value, Inputs, Level 3 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Cash equivalents | 0 | 0 |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
U.S. government agencies |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 189,600,000 | 87,300,000 |
U.S. government agencies | Fair Value, Inputs, Level 1 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
U.S. government agencies | Fair Value, Inputs, Level 2 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 189,600,000 | 87,300,000 |
U.S. government agencies | Fair Value, Inputs, Level 3 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
Corporate debt |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 1,000,000 | 5,100,000 |
Corporate debt | Fair Value, Inputs, Level 1 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
Corporate debt | Fair Value, Inputs, Level 2 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 1,000,000 | 5,100,000 |
Corporate debt | Fair Value, Inputs, Level 3 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
Commercial paper |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 67,900,000 | 14,700,000 |
Commercial paper | Fair Value, Inputs, Level 1 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | 0 |
Commercial paper | Fair Value, Inputs, Level 2 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 67,900,000 | 14,700,000 |
Commercial paper | Fair Value, Inputs, Level 3 |  |  |
Debt securities, available for sale |  |  |
Short-term marketable securities, available-for-sale | 0 | $ 0 |
Equity investment in Tandem Diabetes Care, Inc |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment in Tandem Diabetes Care, Inc. | 42,800,000 |  |
Equity investment in Tandem Diabetes Care, Inc | Fair Value, Inputs, Level 1 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment in Tandem Diabetes Care, Inc. | 42,800,000 |  |
Equity investment in Tandem Diabetes Care, Inc | Fair Value, Inputs, Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment in Tandem Diabetes Care, Inc. | 0 |  |
Equity investment in Tandem Diabetes Care, Inc | Fair Value, Inputs, Level 3 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment in Tandem Diabetes Care, Inc. | $ 0 |  |

X
- Definition Fair Value, Assets, Level 3 Transfers, Amount + References No definition available. + Details
Name: | dxcm_FairValueAssetsLevel3TransfersAmount
Namespace Prefix: | dxcm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesBalanceSheetReportedAmountsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investments in debt securities classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26626-111562 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CashEquivalentsAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock. + References No definition available. + Details
Name: | us-gaap_ConvertibleDebtFairValueDisclosures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(5)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24584-111560 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommercialPaperMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentAxis=dxcm_TandemDiabetesCareIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |