License and Royalty Revenue (Tables)

3 Months Ended

Mar. 31, 2021

License Agreement Revenue Recognition [Abstract]

Summary of Changes in Balances of Receivables, Contract Assets and Deferred Revenue

The following table presents changes in the balances of the Company’s net accounts receivable, contract assets and deferred revenue, as well as other information regarding revenue recognized during the periods presented (in thousands):

	Three Months Ended March 31,
	2021			2020
Accounts receivable, net, current and non-current:
Balance, beginning of period	$	46,266		$	42,303
Additions		18,718			18,142
Deductions		(21,086	)		(11,550	)
Balance, end of period	$	43,898		$	48,895
Contract assets:
Balance, beginning of period	$	350		$	—
Additions		649			350
Deductions		(350	)		—
Balance, end of period	$	649		$	350
Deferred revenue, current and non-current:
Balance, beginning of period	$	4,232		$	3,333
Additions		—			—
Deductions		(108	)		—
Balance, end of period	$	4,124		$	3,333
Revenue recognized during the period from:
Amounts included in deferred revenue at beginning of period	$	108		$	—
Performance obligations satisfied in previous periods	$	18,651		$	10,379

Summary of Accounts Receivables, net

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

	March 31, 2021			December 31, 2020
Current accounts receivable:
Billed to customers	$	30,584		$	30,573
Unbilled		18,698			20,104
Allowance for credit losses		(8,243	)		(7,678	)
Current accounts receivable, net		41,039			42,999
Non-current accounts receivable:
Unbilled		2,859			3,267
Allowance for credit losses		—			—
Non-current accounts receivable, net		2,859			3,267
Total accounts receivable, net	$	43,898		$	46,266

Summary of Changes in Allowance For Credit Losses

The following table presents the changes in the allowance for credit losses related to accounts receivable and contract assets for the three months ended March 31, 2021 (in thousands):

	Accounts Receivable		Contract Assets
Balance at December 31, 2020	$	7,678	$	—
Provision for credit losses		565		—
Write-offs		—		—
Balance at March 31, 2021	$	8,243	$	—

Schedule of License Revenue

The Company recognized the following amounts under the March 2014 License with Novartis Gene Therapies (in thousands):

	Three Months Ended March 31,
	2021		2020
Royalties on net sales of Zolgensma	$	18,263	$	9,978
Total license and royalty revenue	$	18,263	$	9,978
Interest income from licensing	$	6	$	7