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Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) - shares shares in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 01, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Concentration Risk [Line Items]
Securities excluded from net loss per share calculation (in shares)		28	74	72	150
Warranty service periods	10 years
Minimum
Concentration Risk [Line Items]
Warranty service periods				1 year
Maximum
Concentration Risk [Line Items]
Warranty service periods				5 years
Geographic concentration risk | United States
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				98.00%
Revenue | Geographic concentration risk | Countries outside of the United States
Concentration Risk [Line Items]
Concentration risk (less than for one percent)		1.00%	1.00%	1.00%	2.00%
Global Healthcare Systems, Northeast Ohio | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)		23.00%		17.00%	11.00%
Global Healthcare Systems, Northeast Ohio | Accounts receivable | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				18.00%		10.00%
ESCO | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)		23.00%
Customer One | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)			12.00%
Customer Two | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				12.00%
Customer Two | Accounts receivable | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)				28.00%
Atlantic Diving Supply, Inc. | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)		12.00%	40.00%	12.00%	32.00%
Atlantic Diving Supply, Inc. | Accounts receivable | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)						63.00%
U.S. Navy | Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk (less than for one percent)		20.00%	46.00%	18.00%	40.00%

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