Quarterly Financial Data (Unaudited) - Schedule of Quarterly Financial Information (Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2018	Sep. 28, 2018	Dec. 31, 2017	Sep. 29, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unusual or Infrequent Item [Line Items]
Unusual or Infrequent Item, Loss, Gross		$ 800	$ 400	$ 1,200
Deferred tax asset valuation allowance	$ 5,590		2,505			$ 5,590	$ 2,505	$ 2,650	$ 2,349
Enactment of the Tax Cuts and Jobs Act			$ 1,700			1,700	$ 1,704
Unusual or Infrequent Item, Net (Gain) Loss				$ 700
Unusual or Infrequent Item Per Basic Share				$ 0.05
Unusual or Infrequent Item Per Diluted Share				$ 0.05
Domestic Country [Member]
Unusual or Infrequent Item [Line Items]
Deferred tax asset valuation allowance	4,100					$ 4,100
Enactment of the Tax Cuts and Jobs Act	$ 3,800
Employee Severance [Member]
Unusual or Infrequent Item [Line Items]
Unusual or Infrequent Item, Loss, Gross					$ 800
Unusual or Infrequent Item, Net (Gain) Loss					$ 500
Unusual or Infrequent Item Per Basic Share					$ 0.03
Unusual or Infrequent Item Per Diluted Share					$ 0.03
Employee Severance [Member] | Selling General and Administrative Expenses [Member]
Unusual or Infrequent Item [Line Items]
Unusual or Infrequent Item, Loss, Gross		$ 500			$ 400
Employee Severance [Member] | Direct Costs [Member]
Unusual or Infrequent Item [Line Items]
Unusual or Infrequent Item, Loss, Gross					$ 400