Summary of significant accounting policies (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) customer	Dec. 31, 2018 USD ($) customer
Concentration Risk [Line Items]
Allowance for accounts receivable	$ 0	$ 0
Accounts receivable	$ 444	$ 578
Customer Concentration Risk \| Revenue \| Allergan
Concentration Risk [Line Items]
Number of customers \| customer	1	1
Concentration risk percentage	100.00%	75.00%
Customer Concentration Risk \| Accounts Receivable \| Allergan
Concentration Risk [Line Items]
Accounts receivable	$ 400	$ 600

Represents the number of customers.

No definition available.

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

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- Definition

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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