Share-Based Compensation (Details 3) - $ / shares	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement [Abstract]
Number of stock options exercised	57,036	750	213,048	15,967
Weighted average exercise price	$ 1.77	$ 2.20	$ 1.92	$ 4.68

Number of share options (or share units) exercised during the current period.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration