Fair value of financial instruments and marketable securities - Narrative (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2017	Dec. 31, 2016
Financial assets and liabilities measured at fair value on recurring basis
Transfers of assets between Level 1 and Level 2 of the fair value measurement hierarchy	$ 0	$ 0
Realized gains	$ 30,000	$ 0
Warrants
Financial assets and liabilities measured at fair value on recurring basis
Risk-free interest rate (as a percent)	1.38%
Minimum \| Warrants
Financial assets and liabilities measured at fair value on recurring basis
Volatility	69.00%	62.00%
Risk-free interest rate (as a percent)		0.62%
Strike price (in dollars per share)	$ 128.00	$ 128.00
Expected life	2 years 1 month 6 days	4 months 24 days
Maximum \| Warrants
Financial assets and liabilities measured at fair value on recurring basis
Volatility	70.00%	67.00%
Risk-free interest rate (as a percent)		1.34%
Strike price (in dollars per share)	$ 2,520.00	$ 2,520.00
Expected life	2 years 2 months 23 days	2 years 8 months 12 days
Common stock \| Warrants
Financial assets and liabilities measured at fair value on recurring basis
Fair value of shares (in dollars per share)	$ 18.33	$ 10.91
SARs \| Minimum
Financial assets and liabilities measured at fair value on recurring basis
Volatility	67.00%	48.00%
Risk-free interest rate (as a percent)	1.14%	0.44%
Strike price (in dollars per share)	$ 6.76	$ 6.76
Expected life	6 months 7 days	4 days
SARs \| Maximum
Financial assets and liabilities measured at fair value on recurring basis
Volatility	70.00%	71.00%
Risk-free interest rate (as a percent)	1.47%	1.47%
Strike price (in dollars per share)	$ 30.86	$ 30.86
Expected life	2 years 6 months 7 days	3 years
SARs \| Common stock
Financial assets and liabilities measured at fair value on recurring basis
Fair value of shares (in dollars per share)	$ 18.33	$ 10.91

Amount of transfers of assets measured on a recurring basis between Level 1 and Level 2 of the fair value hierarchy.

No definition available.

Name:	ptct_FairValueAssetsTransfersBetweenLevel1AndLevel2Amount
Namespace Prefix:	ptct_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Definition

Agreed upon price for the exchange of the underlying asset.

+ 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 (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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

- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

+ Details

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

- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

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

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_WarrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_StockAppreciationRightsSARSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: