Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Contingent Consideration Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis	$ (307,000)	$ (451,000)
Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,555,000	2,510,000
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	9,674,000	9,630,000
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	9,674,000	9,630,000
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Contingent Consideration Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis	(307,000)	(451,000)
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$ 2,555,000	$ 2,510,000