Trade Accounts Receivable (Tables)

6 Months Ended

Jun. 30, 2019

Receivables [Abstract]

Summary of Trade Accounts Receivable

Trade accounts receivable are recorded at the invoiced amount.

	June 30,			December 31,
	2019			2018
Trade accounts receivable	$	4,259		$	3,903
Allowance for doubtful accounts		(20	)		(15	)
Trade accounts receivable, net	$	4,239		$	3,888
Unpaid deferred revenue included in trade    accounts receivable	$	1,051		$	2,030

Customers Accounted for 10% or More of Trade Accounts Receivable, Net

The following customers accounted for 10% or more of trade accounts receivable, net:

	June 30,			December 31,
	2019			2018
Central Banks		55	%		48	%