Facility Lease - Minimum rental commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Minimum rental commitments under Topic 842
2020	$ 1,159
2021	1,260
2022	1,299
Total lease payments	3,718
Less: imputed interest	(530)
Total	$ 3,188
Minimum rental commitments under Topic 840
2019		$ 1,110
2020		1,142
2021		1,251
2022		1,296
2023		109
Total		$ 4,908

Amount of lessee's undiscounted obligation for lease payments for operating lease.

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Amount of lessee's undiscounted obligation for lease payments for operating lease, due in next fiscal year following latest fiscal year.

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Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year.

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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