Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Highly liquid marketable securities with original maturities			90 days or less
Cash equivalents includes money market securities, commercial paper and pre-refunded municipals			$ 18,568,000	$ 10,436,000
Short-term marketable securities maturity description			Over 90 days that mature in less than one-year
Marketable securities other-than temporary impairments			$ 0
Credit exposure to any one financial institution or type of financial instrument			5% of its cash equivalents and marketable securities or $1,000, whichever is greater
Percentage of credit exposure to any one financial institution or type of financial instrument			5.00%
Maximum amount of credit exposure to any one financial institution or type of financial instrument			$ 1,000,000
Credit exposure limits of cash and cash equivalents and marketable securities			40% of its cash equivalents and marketable securities, or $15,000, whichever is greater
Percentage of credit exposure limits based on cash and cash equivalents and marketable securities			40.00%
Credit exposure limits of cash and cash equivalents and marketable securities under option two			$ 15,000,000
Impairment of goodwill	$ 0	$ 0