Income taxes (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Operating Loss Carryforwards [Line Items] | ||
| Net operating loss carry forwards | $ 168.8 | |
| Portion of federal and state net operating loss carryforwards subject to an 80% limitation on taxable income, that do not expire and will carry forward indefinitely | 20.1 | $ 19.1 |
| Increase (decrease) in deferred tax asset valuation allowance | 3.5 | |
| Federal [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Net operating loss carry forwards | $ 100.3 | |
| Maximum [Member] | Federal [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Net operating loss carry forwards, expiration date | Dec. 31, 2037 |
| X | ||||||||||
- Definition Portion of federal and state net operating loss carryforwards subject to an 80% limitation on taxable income, that do not expire and will carry forward indefinitely. No definition available.
|
| X | ||||||||||
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Expiration date of each operating loss carryforward included in operating loss carryforward, in CCYY-MM-DD format. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- 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.
|
| X | ||||||||||
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|