XML 58 R73.htm IDEA: XBRL DOCUMENT
v3.20.1

LEASES - Narrative (Details) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2020 USD ($) ft² | Mar. 31, 2019 USD ($) | Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items] |  |  |
Additional amortization expense | $ 70 | $ 0 |
Variable lease costs | 637 | $ 601 | $ 900
Facilities |  |  |
Lessee, Lease, Description [Line Items] |  |  |
Accrual for future anticipated variable lease costs | 900 |  | 900
2019 Restructuring Initiative |  |  |
Lessee, Lease, Description [Line Items] |  |  |
Accrual for future anticipated variable lease costs | 2,465 |  | 3,101
2019 Restructuring Initiative | Facilities |  |  |
Lessee, Lease, Description [Line Items] |  |  |
Additional amortization expense | 100 |  | 3,700
Accrual for future anticipated variable lease costs | $ 953 |  | $ 991
North Dallas, Texas |  |  |
Lessee, Lease, Description [Line Items] |  |  |
Square feet under lease | ft² | 107,800 |  |

X
- Definition Operating Lease, Area of Lease + References No definition available. + Details
Name: | sons_OperatingLeaseAreaofLease
Namespace Prefix: | sons_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 5.P.4(b)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
Name: | us-gaap_RestructuringReserve
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of accelerated depreciation charged against earnings associated with exit from or disposal of business activities or restructuring plan. + References No definition available. + Details
Name: | us-gaap_RestructuringReserveAcceleratedDepreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971 + Details
Name: | us-gaap_VariableLeaseCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RestructuringCostAndReserveAxis=us-gaap_FacilityClosingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RestructuringPlanAxis=sons_A2019RestructuringInitiativeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=sons_NorthDallasTexasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |