We extend credit on an unsecured basis to most of our customers. Our exposure to credit losses may increase if our customers are adversely affected by changes in healthcare laws, coverage, and reimbursement, economic pressures or uncertainty associated with local or global economic recessions, disruption associated with the current COVID-19 pandemic, or other customer-specific factors. While we actively manage our credit exposure and work to respond to both changes in our customers’ financial conditions or macroeconomic events, there can be no guarantee we will be able to mitigate all of these risks successfully. Although we have historically not experienced significant credit losses, it is possible that there could be a material adverse impact from potential adjustments of the carrying amount of trade receivables in the future.

We review accounts receivable for uncollectible accounts and provide an allowance for doubtful accounts, which is based upon a review of outstanding receivables, historical collection information, reasonable supportable forecasts and existing economic conditions and we record an allowance that presents the net amount expected to be collected. We evaluate trade accounts receivable for delinquency. We write off delinquent receivables against our allowance for doubtful accounts based on individual credit evaluations, the results of collection efforts, and specific circumstances of customers. We record recoveries of accounts previously written off when received as an increase in the allowance for doubtful accounts. To the extent data we use to calculate these estimates does not accurately reflect bad debts, adjustments to these reserves may be required.

The following sets forth activities in our allowance for credit losses (in thousands):

	Total
Balance as of January 1, 2021	$	1,118
Charges to provision for credit losses		445
Write-off of uncollectible receivables		(290	)
Balance as of June 30, 2021	$	1,273