Stock-Based Compensation - Classification of Stock-Based Compensation Expense Narrative (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) vesting_type $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of award vesting types | vesting_type	3
Weighted-average grant date fair value of options issued (in dollars per share) | $ / shares	$ 4.25	$ 7.02	$ 6.83
Total intrinsic value of options exercised | $	$ 0.9	$ 2.4	$ 3.9
Cash liability for performance-based units | $	$ 0.0
Performance-based awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	0	8,000	67,000
Options vested (in shares)		7,000
Options forfeited in period (in shares)	9,000	16,000	398,000
Stock-based compensation expense | $	$ 0.0	$ 0.1	$ 0.0
Stock-based compensation, maximum number of unvested shares (in shares)	453,000
Total unrecognized compensation cost related to non-vested stock options granted | $	$ 0.3
Weighted-average period for recognition (in years)	2 years 7 months 12 days
Market-based awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested (in shares)	22,000
Options forfeited in period (in shares)	91,000	155,000	554,000
Stock-based compensation expense | $	$ 0.0	$ 0.0	$ 0.2
Stock-based compensation, maximum number of unvested shares (in shares)	136,000
Vesting period (in years)	8 years
Service-based awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	31,000	23,000	52,000
Options forfeited in period (in shares)	8,000	8,000	14,000
Stock-based compensation expense | $	$ 0.3	$ 0.3	$ 0.5
Vesting period (in years)	4 years
Expiration term (in years)	8 years
Total unrecognized compensation cost related to non-vested stock options granted | $	$ 0.3
Weighted-average period for recognition (in years)	2 years 7 months 12 days
Performance Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued (in shares)	153,000	119,000	83,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued (in shares)	81,000	59,000	28,000
Restricted Stock [Member] | Non Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $		$ 0.1
Granted to restricted shares to members of its advisory boards (in shares)	9,000	8,000	8,000
Deferred Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued (in shares)	44,000	46,000	48,000
Percentage of shares vested in lieu of directors fees at the grant date	100.00%
Portion of Director fees matched to deferred stock units	25.00%
Vesting period of deferred stock (in years)	1 year
Deferred stock units, performance-based stock units and restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $	$ 1.3	$ 1.5	$ 1.1
Granted to restricted shares to members of its advisory boards (in shares)	286,000	231,000
Compensation cost not yet recognized | $	$ 4.8
Total fair value of stock-based compensation vested | $	$ 1.1	$ 1.4	$ 1.1