Accounts Receivable

6 Months Ended

Jun. 30, 2022

4. Accounts Receivable

Accounts receivable, net consists of the following (in thousands):

	June 30, 2022			December 31, 2021
Accounts receivable – commercial
Accounts receivable, gross	$	14,869		$	7,939
Wholesaler distribution fees and prompt pay discounts		(2,451	)		(1,696	)
Reserve for returns		(3,173	)		(2,797	)
Total accounts receivable – commercial, net		9,245			3,446
Accounts receivable – collaborations and services
Accounts receivable, gross		5,785			2,060
Allowance for doubtful accounts		—			(767	)
Total accounts receivable – collaborations and services, net		5,785			1,293
Total accounts receivable, net	$	15,030		$	4,739

As of June 30, 2022 and December 31, 2021, the allowance for doubtful accounts for accounts receivable – commercial was de minimis. The Company had three wholesale distributors representing approximately 76% of commercial accounts receivable as of June 30, 2022 and approximately 73% and 72% of gross sales for the three and six months ended June 30, 2022, respectively.

As of June 30, 2022, there was no allowance for credit losses for accounts receivable – collaborations and services. The Company had one collaboration partner, United Therapeutics, that comprised 99% of the collaboration and services net accounts receivable as of June 30, 2022 and approximately 88% and 90% of gross revenue from collaborations and services for the three and six months ended June 30, 2022, respectively.