Convertible Notes Receivable - Additional Information (Details) - USD ($)	May 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Loans And Leases Receivable Disclosure [Line Items]
Convertible notes receivable		$ 5,000,000	$ 5,000,000
Accrued interest		$ 93,000
Convertible Loan Agreement [Member] | Simax Precision Technologies Limited [Member]
Loans And Leases Receivable Disclosure [Line Items]
Funds available in multiple promissory notes	$ 15,000,000
Convertible notes rate of interest	4.25%
Term of repayment for principal amount and outstanding interest	3 years