Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregated Revenues by Timing of Transfer of Goods or Services

The following tables present our revenues disaggregated by timing of transfer of goods or services (in thousands):

	Year Ended December 31, 2019						Year Ended December 31, 2018
	Product Revenue, net		Collaboration and License Revenue		Total		Product Revenue, net		Collaboration and License Revenue		Total
Timing of revenue recognition:
Transferred at a point in time	$	111,644	$	—	$	111,644	$	24,117	$	—	$	24,117
Transferred over time	—		4,996		4,996		—		16,013		16,013
Total	$	111,644	$	4,996	$	116,640	$	24,117	$	16,013	$	40,130

Schedule of Net Product Revenues Disaggregated by Geographic Region

The following table presents our net product revenues disaggregated by geographic region (in thousands):

	Year Ended December 31,
	2019		2018		2017
United States	$	104,708	$	24,117	$	—
Europe	6,936		—		—
Total revenues	$	111,644	$	24,117	$	—

Activity of Product Revenue Reserves

The activities and ending reserve balances for each significant category of product revenue reserves (which constitute variable considerations) were as follows (in thousands):

	Returns			Chargebacks			Others			Total
Balance at December 31, 2017	$	—		$	—		$	—		$	—
Provision related to sales made in:
Current period	2,611			289			633			3,533
Prior period	—			—			—			—
Payments and customer credits issued	(2,312		)	(113		)	(409		)	(2,834		)
Balance at December 31, 2018	$	299		$	176		$	224		$	699
Provision related to sales made in:
Current period	10,254			4,026			3,988			18,268
Prior period	2,373			—			—			2,373
Payments and customer credits issued	(5,366		)	(3,303		)	(1,550		)	(10,219		)
Balance at December 31, 2019	$	7,561		$	899		$	2,661		$	11,121

Schedule of Changes in Contract Assets and Liabilities

The following table presents changes in our contract assets and liabilities for the year ended December 31, 2019 (in thousands):

	Balance at Beginning of Period		Addition		Deduction			Balance at End of Period
Contract assets:
Unbilled - collaboration and license revenue	$	9,880	$	5,628	$	(11,725	)	$	3,783
Total contract assets	$	9,880	$	5,628	$	(11,725	)	$	3,783
Contract liabilities:
Deferred revenue	$	6,335	$	2,628	$	(3,445	)	$	5,518
Total contract liabilities	$	6,335	$	2,628	$	(3,445	)	$	5,518

Significant changes in the contract liabilities balances during the period are as follows (in thousands):

	Year Ended December 31, 2019
Revenue recognized according to the current period performance that was included in the contract liability at the beginning of the period	$	884

Estimated Revenue Expected to be Recognized in Future Related to Performance Obligations

The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied or partially unsatisfied as of December 31, 2019 (in thousands):

Collaborator	Transaction Price Allocated to the Remaining Performance Obligation as of December 31, 2019		Expected Year By Which Revenue Recognition Will Be Completed	Percentage of Revenue Recognized
BMS and Pfizer - 2016 agreement	$	451	2021	96	%
Daiichi Sankyo - 2014 agreement	673		2021	98	%
Daiichi Sankyo - 2016 agreement	2,355		2025	86	%
Bayer - 2016 agreement	1,697		2025	90	%
Total	$	5,176