Summary of Series B Convertible Preferred Stock and Accretion of Dividend (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Stockholders Equity [Line Items]
Dividends earned on Series B preferred stock	$ 304	$ 289	$ 902	$ 859
Series B Convertible Preferred Stock
Stockholders Equity [Line Items]
Balance at beginning of period	24,715	23,539	24,117	22,969
Dividends earned on Series B preferred stock	304	289	902	859
Balance at end of period	$ 25,019	$ 23,828	$ 25,019	$ 23,828
Number of shares at beginning of period	6,179	5,885	6,029	5,742
Cumulative dividends on Series B convertible preferred stock	76	72	226	215
Number of shares at end of period	6,255	5,957	6,255	5,957