Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net loss	$ (46,532)	$ (80,147)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,448	1,664
Change in valuation of warrant liability	3	47
Non-cash interest expense	3,274	2,941
Loss on disposal of asset	47	0
Amortization of premiums on investments	365	1,140
Amortization of debt issuance costs	185	147
Share-based compensation expense	16,914	17,651
Benefit for deferred income taxes	0	(244)
Unrealized foreign currency transaction losses, net	1,648	963
Changes in operating assets and liabilities:
Inventory, net	(2,806)	0
Prepaid expenses and other current assets	(416)	1,163
Trade receivables, net	(6,762)	(8,480)
Deposits and other assets	(463)	(170)
Accounts payable and accrued expenses	12,452	(3,435)
Other liabilities	457	1
Deferred revenue	4,604	587
Net cash used in operating activities	(15,582)	(66,172)
Cash flows from investing activities
Purchases of fixed assets	(579)	(275)
Purchases of marketable securities	(19,467)	(46,256)
Sale and redemption of marketable securities	144,357	89,645
Acquisition, including transaction costs	(76,424)	0
Net cash provided by investing activities	47,887	43,114
Cash flows from financing activities
Proceeds from exercise of options	535	34
Proceeds from shares issued under employee stock purchase plan	557	0
Debt issuance costs related to secured term loan	(432)	0
Proceeds from issuance of secured term loan	40,000	0
Net cash provided by financing activities	40,660	34
Effect of exchange rate changes on cash	1,725	660
Net increase in cash and cash equivalents	74,690	(22,364)
Cash and cash equivalents, beginning of period	58,321	58,022
Cash and cash equivalents, end of period	133,011	35,658
Supplemental disclosure of cash information
Cash paid for interest	2,474	2,263
Cash paid for income taxes	334	264
Supplemental disclosures of non-cash information related to investing and financing activities
Change in unrealized (loss) gain on marketable securities, net of tax	$ (31)	$ 618

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.