Nature of operations and summary of significant accounting policies and going concern (Income Taxes) (Details) - USD ($)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Accounting Policies [Abstract]
Effective tax rate	0.00%	0.00%
Deferred tax benefit	$ 0
Uncertain tax positions	0		$ 0
Net operating loss carryforwards subject to limitation	$ 760,067,000

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Name:	us-gaap_DeferredIncomeTaxExpenseBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration