Annual report pursuant to Section 13 and 15(d)

Intangible Assets, Net - Additional Information (Details)

v3.10.0.1
Intangible Assets, Net - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]      
Amortization expense $ 61,000 $ 47,000 $ 37,000