Amount of the debt instrument due as of the balance sheet date.

No definition available.

Name:	hcm_DebtInstrumentAmountsDue
Namespace Prefix:	hcm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of facility agreements with banks entered into by the Group through its subsidiary.

+ References

No definition available.

+ Details

Name:	hcm_NumberOfFacilityAgreements
Namespace Prefix:	hcm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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(22))
-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 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: 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(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentsOfDebtIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=hcm_HongKongInterbankOfferedRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_NotesPayableToBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=hcm_FirstCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=hcm_SecondCreditFacilityMember
Namespace Prefix:
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Bank Borrowings - Loan Facilities (Details)		1 Months Ended
Bank Borrowings - Loan Facilities (Details)	Feb. 28, 2017 HKD ($) agreement	Nov. 30, 2017 HKD ($)	Nov. 30, 2017 USD ($)	Feb. 28, 2017 HKD ($)	Nov. 30, 2015 HKD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Feb. 28, 2017 USD ($)	Nov. 30, 2015 USD ($)
Revolving loan facility
Bank Borrowings
Term					3 years
Aggregate amount of credit facilities					$ 234,000,000					$ 30,000,000
Amount drawn from the credit facility	$ 20,000,000			$ 20,000,000					$ 2,564,000
Amount due under this facility						$ 0	$ 0
Revolving loan facility \| HIBOR
Bank Borrowings
Basis spread on variable rate					1.25%
Unsecured credit facility
Bank Borrowings
Aggregate amount of credit facilities	$ 546,000,000	$ 400,000,000		$ 546,000,000				$ 51,282,000	70,000,000
Number of facility agreements entered \| agreement	2
Unsecured credit facility \| Term loan
Bank Borrowings
Term		3 years	3 years
Aggregate amount of credit facilities		$ 210,000,000						26,923,000
Amount of upfront fee		$ 1,575,000	$ 202,000
Unsecured credit facility \| Term loan \| HIBOR
Bank Borrowings
Basis spread on variable rate		1.50%	1.50%
Unsecured credit facility \| Revolving loan facility
Bank Borrowings
Term		18 months	18 months
Aggregate amount of credit facilities		$ 190,000,000						$ 24,359,000
Amount drawn from the credit facility						0	0
Unsecured credit facility \| Revolving loan facility \| HIBOR
Bank Borrowings
Basis spread on variable rate		1.25%	1.25%
First unsecured credit facility \| Term loan
Bank Borrowings
Term				18 months
Aggregate amount of credit facilities	$ 156,000,000			$ 156,000,000					20,000,000
First unsecured credit facility \| Term loan \| HIBOR
Bank Borrowings
Basis spread on variable rate				1.25%
First unsecured credit facility \| Revolving loan facility
Bank Borrowings
Term				18 months
Aggregate amount of credit facilities	195,000,000			$ 195,000,000					25,000,000
Amount drawn from the credit facility						0	0
First unsecured credit facility \| Revolving loan facility \| HIBOR
Bank Borrowings
Basis spread on variable rate				1.25%
Second unsecured credit facility \| Term loan
Bank Borrowings
Term				18 months
Aggregate amount of credit facilities	78,000,000			$ 78,000,000					10,000,000
Second unsecured credit facility \| Term loan \| HIBOR
Bank Borrowings
Basis spread on variable rate				1.25%
Second unsecured credit facility \| Revolving loan facility
Bank Borrowings
Term				18 months
Aggregate amount of credit facilities	$ 117,000,000			$ 117,000,000					$ 15,000,000
Amount drawn from the credit facility						$ 0	$ 0
Second unsecured credit facility \| Revolving loan facility \| HIBOR
Bank Borrowings
Basis spread on variable rate				1.25%