Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Summary of Allowance for Doubtful Accounts

A summary of activity in the Company’s allowance for doubtful accounts is as follows (in thousands):

Balance at December 31, 2012	$	4,278
Additions charged to provision for doubtful accounts		10,950
Accounts written off, net of recoveries		(1,908	)
Balance at December 31, 2013	$	13,320
Additions charged to provision for doubtful accounts		11,391
Accounts written off, net of recoveries		(16,243	)
Balance at December 31, 2014	$	8,468
Additions charged to provision for doubtful accounts		18,113
Accounts written off, net of recoveries		(9,704	)
Balance at December 31, 2015	$	16,877

Schedule of Useful Life of Property Plant and Equipment

Depreciation is calculated using the straight-line method over the estimated economic useful lives of the assets, as follows:

		Range of Lives
Computer software and equipment		3 years
Buildings		36 years
Furniture, fixtures and equipment		5 years
Vehicles		5 years
Equipment under capital lease		3-5 years
Leasehold improvements		Life of the asset or lease,
		whichever is less

Schedule of Accrued Liabilities Reflected as a Current Liability in the Accompanying Consolidated Balance Sheet

The Company’s accrued liabilities, reflected as a current liability in the accompanying consolidated balance sheets, consist of the following (in thousands):

	Year Ended December 31,
	2014		2015
Accrued payroll liabilities	$	6,536	$	10,090
Accrued litigation settlement		158		800
Accrued legal fees		317		479
Income taxes payable		—		2,527
Accrued property, plant, and equipment		—		1,487
Other		3,400		6,270
Total accrued liabilities	$	10,411	$	21,653