Contract Liabilities - Performance Obligations (Details)	Dec. 29, 2018 USD ($)
Contract Liabilities:
Revenue, remaining peformance obligation	$ 10,177,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-12-30
Contract Liabilities:
Revenue, remaining peformance obligation	$ 1,744,900
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-12-29
Contract Liabilities:
Revenue, remaining peformance obligation	$ 1,608,400
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-12-27
Contract Liabilities:
Revenue, remaining peformance obligation	$ 1,469,600
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-12-26
Contract Liabilities:
Revenue, remaining peformance obligation	$ 1,324,700
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Contract Liabilities:
Revenue, remaining peformance obligation	$ 1,153,400
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-12-31
Contract Liabilities:
Revenue, remaining peformance obligation	$ 2,876,300
Future estimated revenue to be recognised related to performance obligations
Duration of expected recognition period for remaining performance obligation

No definition available.

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

- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

+ Details

Name:	us-gaap_RevenueRemainingPerformanceObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Definition

Period in which remaining performance obligation is expected to be recognized as revenue, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

+ Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2018-12-30
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2019-12-29
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2020-12-27
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2021-12-26
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2023-01-01
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2023-12-31
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: