Stock-Based Compensation - Additional Information (Detail)		1 Months Ended	3 Months Ended				9 Months Ended
	Jun. 30, 2017 USD ($) shares	Feb. 28, 2017 shares	Sep. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) OfferingPeriod $ / shares shares	Sep. 30, 2016 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant | shares			4,500,000				4,500,000
Stock-based compensation expense			$ 2,347,000			$ 2,012,000	$ 6,833,000	$ 6,004,000
Unrecognized stock-based compensation expense			$ 17,900,000				$ 17,900,000
Unrecognized stock-based compensation, expected to be recognized, weighted average period							2 years 7 months 7 days
Stock options exercisable | shares			708,209				708,209
Weighted average exercise price | $ / shares			$ 43.91				$ 43.91
Weighted average remaining contractual life							4 years 3 months 19 days
Weighted average fair value per share of options granted | $ / shares							$ 18.90
Number of offerings per year | OfferingPeriod							2
Net proceeds from employee stock purchase plan							$ 1,011,000	$ 786,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 152,000				$ 444,000
Percentage of common stock on fair market value							85.00%
Common stock reserved for future issuance | shares			1,000,000				1,000,000
Employee stock purchase plan, employees contribution	$ 1,021,000		$ 599,000	$ 1,021,000			$ 599,000
Net proceeds from employee stock purchase plan	$ 1,011,000
Employee stock purchase plan, shares purchased | shares	18,655
Equity Incentive Plan [Member] | 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares were authorized under 2010 Equity Incentive Plan | shares		1,024,868
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vest, period							4 years
Stock options contractual term, from the date of grant							seven to ten years
Stock Options [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options contractual term range							7 years
Stock Options [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options contractual term range							10 years
Performance Share Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 0		$ 169,000
Stock options vest, period		3 years
Stock-based compensation reversing benefit				$ 169,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vest, period							4 years
Number of RSU's vested and not issued during the period | shares							30,907
Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards units vest over, period							1 year