Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Additional Information (Detail)

v3.19.1
Marketable Securities - Additional Information (Detail)
3 Months Ended 12 Months Ended
Mar. 31, 2019
USD ($)
Security
Dec. 31, 2018
USD ($)
Security
Marketable Securities [Abstract]    
Maturity period classified current investments Less than one year Less than one year
Number of securities in unrealized loss position for less than one year | Security 11 21
Aggregate fair value of debt securities | $ $ 10,570,964 $ 18,551,296