| Lease Agreements - Leased facilities (Details) | 3 Months Ended | 
|---|---|
| Mar. 31, 2021  facility | |
| Leased facilities, Emeryville, California | |
| Leases | |
| Operating leases, number of leased facilities | 1 | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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| X | ||||||||||
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- Definition Operating leases, number of leased facilities. No definition available. 
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| X | ||||||||||
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- Details 
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