v3.21.1

Leases - Schedule of operating and finance leases (Details) - USD ($) $ in Thousands | Jan. 31, 2021 | Feb. 01, 2020 | Jan. 31, 2020
--- | --- | --- | ---
Leases [Abstract] |  |  |  |  |  |
Operating Lease, Liability, Statement of Financial Position [Extensible List] |  | us-gaap:Liabilities |  |  |  |
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] |  | Property and equipment, net of accumulated depreciation and amortization of $40,148 and $35,551 |  |  |  |
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List] |  | Long-term debt and finance lease liabilities |  |  |  |
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] |  | Long term debt and finance lease liabilities |  |  |  |
Lease right-of-use assets |  | $ 2,654 | [1] | $ 2,741 | $ 0 | [1]
Lease liabilities, current | [1] | 1,087 |  |  | 0 |
Lease liabilities, noncurrent | [1] | 1,899 |  |  | 0 |
Total operating lease liabilities |  | 2,986 |  |  |  |
Property and equipment, at cost |  | 19,933 |  |  |  |
Accumulated depreciation |  | (10,389) |  |  | (7,724) |
Property and equipment, net |  | 9,544 |  |  |  |
Lease liabilities (included in Current portion of debt and finance leases) |  | 3,820 |  |  |  |
Lease liabilities, noncurrent (included in Long-term debt and finance leases) |  | 5,882 |  |  |  |
Total finance lease liabilities |  | $ 9,702 |  |  | $ 3,612 |
[1] | Figures as of January 31, 2021 reflect the Company's February 1, 2020 adoption of Accounting Standards Codification No. 842, Leases (ASC 842). For additional details, see Note 3(ac), "Summary of significant accounting policies — Impact of recently adopted accounting pronouncements."

X
- Definition Finance Lease, Right-Of-Use Asset, Gross + References No definition available. + Details
Name: | phr_FinanceLeaseRightOfUseAssetGross
Namespace Prefix: | phr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918701-209980 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Indicates line item in statement of financial position that includes current finance lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918631-209977 + Details
Name: | us-gaap_FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from finance lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseLiabilityNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Indicates line item in statement of financial position that includes noncurrent finance lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918631-209977 + Details
Name: | us-gaap_FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount, after accumulated amortization, of right-of-use asset from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_FinanceLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated amortization of right-of-use asset from finance lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918638-209977 + Details
Name: | us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Indicates line item in statement of financial position that includes finance lease right-of-use asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918631-209977 + Details
Name: | us-gaap_FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiabilityNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Indicates line item in statement of financial position that includes operating lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918631-209977 + Details
Name: | us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | srt-types:extensibleListItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant