Stock-Based Compensation Plans - Additional Information (Detail) - USD ($)				12 Months Ended			60 Months Ended
	Jan. 31, 2017	Mar. 15, 2016	Mar. 10, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining available shares for issuance under the plan				7,332,533
Stock Option Awards expiry range				5 years
Stock Option Awards granted							0
Options outstanding				970,000	1,085,000	1,120,000	970,000	1,237,000
Compensation expense to purchase shares under the ESPP				$ 207,000	$ 144,000	$ 185,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of authorize payroll deductions				15.00%			15.00%
Maximum Amount of outstanding stock to be subscribed				$ 25,000
Company reserved shares of common stock for issuance under the ESPP				600,000			600,000
Employees purchase shares				64,000	37,000	31,000
Compensation expense to purchase shares under the ESPP				$ 19,000	$ 12,000	$ 11,000
Shares remain available for issuance under the ESPP				186,174			186,174
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expired unexercised	750,000
Options outstanding	220,000
Exercise price of options unexercised	$ 3.04
Stock Option Awards expiration date	Mar. 17, 2018
Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Option Awards expiry range				10 years
Restricted stock | Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing market price per share of common stock		$ 2.30	$ 2.44
Compensation awarded restricted stock units		146,000	141,000