Area of a real estate property.

No definition available.

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

- Definition

Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84164758&loc=d3e45023-112735

+ Details

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Period Type:	instant

- 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

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Balance Type:	na
Period Type:	duration

- Definition

The adjustment to reduce the value of existing agreements that specify the lessee's rights to use the leased property. This expense is charged when the estimates of future profits generated by the leased property are reduced.

+ References

+ Details

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

- Definition

Contractually required future rental payments receivable on noncancelable subleasing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717

+ Details

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

- Definition

The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 3)
-URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697

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

- Definition

Amount of other expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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- Details

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- Details

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Restructuring Charges - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
Restructuring Charges - Narrative (Details) $ in Thousands	Sep. 30, 2017 USD ($) ft²	Jun. 25, 2016 USD ($)	Dec. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Aug. 31, 2017 ft²	Apr. 14, 2016 ft²
Capital Leased Assets [Line Items]
Sublease loss liability			$ (1,069)
Related lease expense			(500)	$ (100)
Capital lease obligations, current	$ 3,100
Restructuring charges	2,600		2,620
Impairment of leasehold	$ 500		$ 500
Massachusetts
Capital Leased Assets [Line Items]
Area of real estate property \| ft²						108,743
Massachusetts \| Property Subject to Operating Lease
Capital Leased Assets [Line Items]
Area of real estate property \| ft²	25,812				25,812	10,362
Sublease loss liability		$ 500
Related lease expense		$ 200