Name:	thrx_BusinessSeparationAbstract
Namespace Prefix:	thrx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the number of common stock distributed as form of dividend for each common stock held by parent company associated with the separation from parent company on completion of spin-off.

+ References

No definition available.

+ Details

Name:	thrx_CommonStockStockDividendRatio
Namespace Prefix:	thrx_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of cash, cash equivalents and marketable securities contributed to another entity due to business separation activities.

+ References

No definition available.

+ Details

Name:	thrx_ContributionOfCashAndCashEquivalentsAndMarketableSecuritiesInBusinessSeparation
Namespace Prefix:	thrx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the percentage of economic interest in any future payments made under the agreements.

+ References

No definition available.

+ Details

Name:	thrx_PercentageOfEconomicInterestOnFuturePaymentsUnderAgreements
Namespace Prefix:	thrx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	thrx_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix:	thrx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Balance held at close of period in number of shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 4

-Subparagraph (SX 210.12-12C.Column B)

-URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611225-123010

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 6

-Subparagraph (SX 210.12-14.Column B)

-URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611322-123010

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-12.Column B)

-URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611133-123010

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12C

-Paragraph Column B

-Article 12

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12

-Paragraph Column B

-Article 12

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 14

-Paragraph Column B

-Article 12

+ Details

Name:	us-gaap_InvestmentOwnedBalanceShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 2: 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_RestrictedCashAndCashEquivalentsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	invest_InvestmentIssuerAxis=thrx_TheravanceBiopharmaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=thrx_GSKMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Description of Operations and Summary of Significant Accounting Policies (Details) (USD $)	0 Months Ended		12 Months Ended
	Jun. 02, 2014	Jun. 01, 2014	Dec. 31, 2014	Dec. 31, 2013
Business Separation
Cash, cash equivalents and marketable securities contributed to Theravance Biopharma		$ 393,000,000
Number of ordinary shares of Theravance Biopharma issued for every share of Theravance	0.286thrx_CommonStockStockDividendRatio
Cash and Cash Equivalents
Restricted cash			0	$ 833,000
Theravance Biopharma \| Common stock
Business Separation
Number of ordinary shares owned as marketable securities (in shares)			436,802
GSK \| LABA collaboration and Strategic Alliance agreements
Description of operations and summary of significant accounting policies
Percentage of economic interest in any future payments made under the agreements			15.00%