Cash and cash equivalents Cash and cash equivalents	6 Months Ended
Jun. 30, 2020
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents Disclosure [Text Block]	Cash and cash equivalentsCash and cash equivalents includes $15.0 million and $10.1 million of short-term deposits with original maturities of less than three months, at June 30, 2020 and December 31, 2019, respectively.

The entire disclosure for cash and cash equivalent footnotes, which may include the types of deposits and money market instruments, applicable carrying amounts, restricted amounts and compensating balance arrangements. Cash and equivalents include: (1) currency on hand (2) demand deposits with banks or financial institutions (3) other kinds of accounts that have the general characteristics of demand deposits (4) short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments maturing within three months from the date of acquisition qualify.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_CashAndCashEquivalentsDisclosureTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration