This line item represents the face amount of each note converted or convertible to common stock.

No definition available.

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

+ References

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

The price per share of the conversion feature embedded in the debt instrument.

+ References

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-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031898-161870

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

- Definition

The number of equity instruments that the holder of the debt instrument would receive if the debt was converted to equity.

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the debt agreement requires the first payment to be made, in CCYY-MM-DD format.

+ References

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

- Definition

Face (par) amount of debt instrument at time of issuance.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
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Data Type:	xbrli:dateItemType
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.

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

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

- 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.

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
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

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Name:	us-gaap_ProceedsFromLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=plab_ConvertibleSeniorNotesDueOnApril2019Member
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=plab_ProjectLoanDueInNovember2025Member
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Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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Period Type:

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Name:	us-gaap_DebtInstrumentAxis=plab_AmendedAndRestatedCreditAgreementMember
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DEBT (Details) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended
DEBT (Details) $ / shares in Units, $ in Thousands	Feb. 28, 2019 USD ($)	Apr. 30, 2016 USD ($) shares $ / shares	Jan. 31, 2015 USD ($) shares $ / shares	Jan. 27, 2019 USD ($)	Oct. 31, 2018 USD ($)	Mar. 31, 2011 USD ($)
Long-term debt [Abstract]
Debt				$ 86,131	$ 57,453
Current portion				(61,647)	(57,453)
Long-term debt noncurrent				24,484	0
Short Term Debt Due in February 2019 [Member]
Long-term debt [Abstract]
Debt				$ 3,720	0
Interest rate percentage				4.90%
Maturity date of debt				Feb. 28, 2019
Term of loan				90 days
3.25% Convertible Senior Notes due on April 2019 [Member]
Long-term debt [Abstract]
Debt				$ 57,482	57,453
Face amount of debt				$ 57,500
Interest rate percentage				3.25%
Maturity date of debt				Apr. 01, 2019
Number of shares each note is convertible to (in shares) \| shares			96
Face amount of each note converted			$ 1
Conversion price per share (in dollars per share) \| $ / shares			$ 10.37
Project Loan Due in November 2025 [Member]
Long-term debt [Abstract]
Debt				$ 14,824	0
Interest rate percentage				4.90%
Maturity date of debt				Dec. 31, 2025
Date of first required payment				Jun. 30, 2020
Maximum borrowing capacity				$ 50,000
Project Loan Due in November 2025 [Member] \| Subsequent Event [Member]
Long-term debt [Abstract]
Date of first required payment	Jun. 30, 2023
Proceeds from credit facility	$ 11,400
Working Capital Loan due in January 2022 [Member]
Long-term debt [Abstract]
Debt				$ 10,105	$ 0
Interest rate percentage				5.00%
Basis spread on variable rate				0.6775%
Maturity date of debt				Jan. 31, 2022
Date of first required payment				May 31, 2019
Maximum borrowing capacity				$ 25,000
Amount outstanding under credit facility				$ 13,800
Amended and Restated Credit Agreement [Member]
Long-term debt [Abstract]
Maturity date of debt				Sep. 30, 2023
Current borrowing capacity				$ 50,000
Maximum borrowing capacity				100,000
Amount outstanding under credit facility				0
Available borrowing capacity				$ 50,000
Effective interest rate				2.50%
3.25% Convertible Senior Notes due in April 2016 [Member]
Long-term debt [Abstract]
Face amount of debt						$ 57,500
Interest rate percentage		3.25%
Maturity date of debt		Apr. 01, 2016
Number of shares each note is convertible to (in shares) \| shares		96
Face amount of each note converted		$ 1
Conversion price per share (in dollars per share) \| $ / shares		$ 10.37