Stockholders' Equity - Additional Information (Detail) - USD ($)			12 Months Ended
	Apr. 10, 2018	Jun. 15, 2017	Dec. 31, 2018	Dec. 31, 2017
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance			15,933,782
Shares of common stock issued	3,450,000
Net proceeds received after deducting underwriters' discounts and commissions and offering costs			$ 27,967,000	$ 15,000,000
Underwriters' Option [Member]
Class Of Stock [Line Items]
Shares of common stock issued	450,000
Purchase price per share	$ 8.60
Net proceeds received after deducting underwriters' discounts and commissions and offering costs	$ 28,000,000
Private Placement [Member]
Class Of Stock [Line Items]
Shares of common stock issued		1,552,795
Purchase price per share		$ 9.66
Aggregate purchase price		$ 15,000
Volume-weighted average trading price of common stock trading days		30 days
Percentage of volume-weighted average trading price of common stock		95.00%
Volume-weighted average trading price of common stock trading days ended on		Jun. 14, 2017
Series A Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, shares authorized			1,000,000	1,000,000
Preferred Stock, shares issued			39,442	37,544
Preferred Stock, shares outstanding			39,442	37,544
Preferred stock dividend percentage received			4.00%
Preferred stock redemption price paid			$ 10.00
Preferred stock dividends issued			1,898	1,078
Dividends in arrears			$ 0
Preferred stock convertible into common stock			1.66611
Preferred Stock, par value			$ 0.001	$ 0.001
Preferred stock voting rights			Each share of the Series A convertible preferred stock is entitled to one vote for each share of common stock into which the preferred stock is convertible.
Preference of preferred stock			$ 10.00
Preferred stock redemption period			Two years
Series A Convertible Preferred Stock [Member] | Minimum [Member]
Class Of Stock [Line Items]
Preferred Stock, par value			$ 11.20
Series A Convertible Preferred Stock [Member] | StarTrak Systems LLC [Member]
Class Of Stock [Line Items]
Preferred Stock, shares issued			183,550
Preferred Stock, shares outstanding			39,442
Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, shares authorized			50,000,000