Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of changes in the allowance for doubtful accounts

Changes in the allowance for doubtful accounts for continuing operations are as follows (in thousands):

	Year ended December 31,
	2017			2016			2015
Balance, beginning of year	$	664		$	709		$	510
Charged to provision for doubtful accounts	113			558			367
Write-offs	(44		)	(603		)	(168		)
Balance, end of year	$	733		$	664		$	709

Schedule of depreciation or amortization of property and equipment

Depreciation or amortization of property and equipment, including assets held under capital leases, is calculated using the straight-line method over the asset’s estimated useful life as follows:

Buildings and leasehold improvements	2-30 years
Machinery, equipment, and rental tools	7-10 years
Furniture and fixtures	3 years
Transportation equipment	2-5 years
Computer equipment and software	3-7 years