Balance Sheets-Additional Information (Detail Textuals) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Jul. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Additional Information Of Balance Sheet [Line Items]
Equity method investments		$ 3,141
Amount of acquired business approximately		9,838	$ 15,000
Amount of acquisition payable in January 2019		3,775
MJ Biologics, Inc. ("MJB")
Additional Information Of Balance Sheet [Line Items]
Total amount due for business acquisition paid	$ 12,775
Amount of acquired business approximately	$ 9,000
Amount of acquisition payable in January 2019		$ 3,775