Summary of Significant Accounting Policies and Other Items (Tables)

12 Months Ended

Dec. 31, 2018

Preparation Of Interim Financial Statements And Other Items

Rollforward of the allowance for doubtful accounts

	Balance at								Balance at
	Beginning of		Expense						End of
	Period		(recovery)		Write off		Other		Period
Year Ended December 31, 2018	$	740	$	—	$	(164)	$	—	$	576
Year Ended December 31, 2017		851		(100)		(3)		(8)		740
Year Ended December 31, 2016		1,208		(357)		—		—		851

Rollforward of inventory obsolescence reserve

	Balance at								Balance at
	Beginning of		Expense						End of
	Period		(recovery)		Write off		Other		Period
Year Ended December 31, 2018	$	5,885	$	1,451	$	—	$	(26)	$	7,310
Year Ended December 31, 2017		4,770		1,259		(103)		(41)		5,885
Year Ended December 31, 2016		3,184		1,851		(265)		—		4,770

Schedule of PP&E useful lives

Land		N/A
Buildings and improvements	5	-	39	years
Machinery and equipment			7	years
Vehicles under capital lease			3	years
Rental equipment	2	-	5	years
Furniture and fixtures			5	years
Computers and software	3	-	5	years

Schedule of Property plant and equipment Net

	December 31,
	2018		2017
Land	$	3,614	$	2,241
Buildings and improvements		20,803		11,657
Machinery and equipment		47,606		43,528
Vehicles under capital lease		25,165		15,557
Rental equipment		124,002		85,292
Furniture and fixtures		1,623		1,110
Computers and software		3,094		2,636
Gross property and equipment		225,907		162,021
Less: Accumulated depreciation		(96,412)		(72,917)
Net property and equipment		129,495		89,104
Construction in progress		12,559		5,550
Total property and equipment, net	$	142,054	$	94,654

Schedule of depreciation expense by income statement caption

	Year Ended December 31,
	2018		2017		2016
Cost of product revenue	$	3,262	$	3,169	$	2,869
Cost of rental revenue		17,997		14,912		15,121
Cost of field service and other revenue		8,456		4,786		2,659
Selling, general and administrative expenses		438		404		592
Total depreciation	$	30,153	$	23,271	$	21,241

Schedule of accrued expenses and other current liabilities

	December 31,
	2018		2017
Payroll, incentive compensation, payroll taxes and benefits	$	7,842	$	4,033
Income based tax payable		2,061		526
Accrued international freight		1,418		851
Taxes other than income		1,414		1,375
Deferred revenue		1,110		765
Product warranties		293		343
Accrued insurance		—		1,059
Accrued interest		24		161
Other		1,488		1,446
Total	$	15,650	$	10,559