Revenue Recognition (Tables)

3 Months Ended

Mar. 31, 2019

Revenue Recognition

Schedule of revenue from United States, Canada and all other international dealers and distributors combined

The following table sets forth revenue from the United States, Canada and all other international dealers and distributors combined (in thousands):

	Three Months Ended
	March 31,
	2019			2018
Revenue-United States	$	41,003		$	40,964
Revenue-Canada		5,171			5,264
Revenue-all other international sources		14,251			12,921
Total revenue	$	60,425		$	59,149
International revenue (excluding Canada) as a percent of total revenue		24	%		22	%

Summary of changes in the allowance for doubtful accounts

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

	Allowance
Balance at December 31, 2018	$	1,529
Provision		8
Write-offs		(291)
Balance at March 31, 2019	$	1,246

Schedule of changes in deferred revenue

The following table presents the changes in deferred revenue for the three months ended March 31, 2019 (in thousands):

	Deferred Revenue
Balance at December 31, 2018	$	8,699
Deferred revenue		4,593
Recognition of deferred revenue		(4,548)
Balance at March 31, 2019	$	8,744