Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (115,314)	$ (119,499)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,477	2,079
Change in valuation of warrant liability	44	(152)
Non-cash interest expense	4,487	736
Amortization of premiums on investments	1,610	1,319
Amortization of debt issuance costs	224	37
Share-based compensation expense	26,610	26,130
Benefit for deferred income taxes	(222)	0
Unrealized foreign currency transaction losses, net	1,401	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,095	(748)
Trade receivables, net	(16,035)	(3,582)
Deposits and other assets	(154)	183
Accounts payable and accrued expenses	2,080	2,871
Other long-term liabilities	682	(69)
Deferred revenue	768	(3,310)
Net cash used in operating activities	(90,247)	(94,005)
Cash flows from investing activities
Purchases of fixed assets	(540)	(1,764)
Purchases of marketable securities	(73,692)	(134,299)
Sale and redemption of marketable securities	155,582	167,082
Net cash provided by investing activities	81,350	31,019
Cash flows from financing activities
Proceeds from exercise of options	926	8,689
Debt issuance costs related to convertible notes	0	(4,650)
Proceeds from issuance of convertible notes	0	150,000
Net cash provided by financing activities	926	154,039
Effect of exchange rate changes on cash	235	(89)
Net (decrease) increase in cash and cash equivalents	(7,736)	90,964
Cash and cash equivalents, beginning of period	58,022	49,748
Cash and cash equivalents, end of period	50,286	140,712
Supplemental disclosure of cash information
Cash paid for interest	4,513	0
Cash paid for income taxes	633	0
Supplemental disclosures of non-cash information related to investing and financing activities
Change in unrealized gain (loss) on marketable securities, net of tax	$ 429	$ (582)

Represents change in the unrealized gain (loss) on marketable securities in noncash investing and financing activities.

No definition available.

Name:	ptct_ChangeInUnrealizedGainLossOnMarketableSecurities
Namespace Prefix:	ptct_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.