Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2021

Schedules of Concentration of Risk, by Risk Factor

A significant customer is a biopharmaceutical customer or a clinical testing payer that represents 10% or more of the Company’s total revenue or accounts receivable balance. Revenue attributable to each significant customer, including its affiliated entities, as a percentage of the Company’s total revenue, for the respective period, and accounts receivable balance attributable to each significant customers, including its affiliated entities, as a percentage of the Company’s total accounts receivable balance, at the respective condensed consolidated balance sheet date, are as follows:


	Revenue								Accounts Receivable, Net
	Three Months Ended June 30,				Six Months Ended June 30,				June 30, 2021		December 31, 2020
	2021		2020		2021		2020

	(unaudited)								(unaudited)
Customer A	*		*		*		14	%	*		11	%
Customer B	29	%	23	%	27	%	21	%	*		13	%

Customer C	*		10	%	*		*		*		12	%
Customer D	*		*		*		*		16	%	11	%

* less than 10%

Schedule of Contractual Receivables and Related Credit Loss

The following table presents the receivable and the related credit loss amounts:


	Gross Amount				Allowance for Credit Losses								Net Amount
	June 30, 2021		December 31, 2020		Three and Six Months Ended June 30, 2021								June 30, 2021		December 31, 2020
					Beginning Balance		Charged to (Reversed from) Other Income (Expense), Net		Reclassi-fication		Ending Balance

	(unaudited)				(unaudited)								(unaudited)
	(in thousand)
Prepaid expenses and other current assets	$	1,100	$	—	$	—	$	—	$	(1,100)	$	(1,100)	$	—	$	—
Other assets	5,900		7,000		(7,000)		—		1,100		(5,900)		—		$	—