Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Schedules of changes in the allowance for doubtful accounts

The following table presents the changes in the allowance for doubtful accounts (in thousands):



	Year Ended December 31,
	2016			2015			2014
Balance at beginning of year	$	581		$	890		$	454
Provision	863			412			829
Acquisitions	—			—			400
Divestitures	(230		)	—			—
Writeoffs, net of recoveries	(556		)	(721		)	(793		)
Balance at end of year	$	658		$	581		$	890

Schedule of estimated useful lives of property and equipment

The estimated useful lives of property and equipment are as follows:



Computer hardware and equipment	3 - 5 years
Purchased software and licenses	3 - 5 years
Furniture and fixtures	7 years
Leasehold improvements	Lesser of estimated useful life or lease term

Property and equipment consisted of the following (in thousands) at:



	December 31, 2016			December 31, 2015
Equipment (including equipment under capital lease of $6,087 and $6,199 at December 31, 2016 and 2015, respectively)	$	11,317		$	11,599
Furniture and fixtures (including furniture under capital lease of $0 and $143 at December 31, 2016 and 2015, respectively)	205			484
Leasehold improvements	729			819
Accumulated depreciation (including for equipment and furniture under capital lease of $2,961 and $2,218 at December 31, 2016 and 2015, respectively)	(7,895		)	(6,901		)
Property and equipment, net	$	4,356		$	6,001

Schedule of weighted-average grant-date fair value assumptions

The following table summarizes the weighted-average grant-date fair value of options granted in 2016, 2015, and 2014 and the assumptions used to develop their fair values. As there was no public market for its common stock prior to November 2014, the Company estimates the volatility of its common stock based on the volatility of publicly traded shares of comparable companies' common stock. The Company's decision to use the volatility of comparable stock was based upon the Company's assessment that this information is more representative of future stock price trends than the Company's historical volatility. The Company estimates the expected term using the simplified method, which calculates the expected term as the midpoint between the vesting date and the contractual termination date of each award. The dividend yield assumption is based on historical and expected future dividend payouts. The risk-free interest rate is based on observed market interest rates appropriate for the term of each options.



	Year Ended December 31,
	2016	2015	2014
Weighted average grant-date fair value of options	$3.23	$3.01	$3.76
Expected volatility	42.5%	42.5% - 44.0%	54.1% - 55.2%
Risk-free interest rate	1.2%	1.7% - 1.9%	1.6% - 1.9%
Expected life in years	5.93	5.93	6.29
Dividend yield	—	—	—