Share-Based Payments - Additional Information (Details) - USD ($)				1 Months Ended	12 Months Ended
	Sep. 20, 2016	Sep. 14, 2016	Mar. 14, 2016	Dec. 31, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 21, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Stock incentive plan, reserved shares of common stock (in shares)					4,133,703	3,596,681
Number of shares reserved for issuance (in shares)					786,431
Stock options granted in connection with acquisition	650,000
Purchase price of shares authorized (in dollars per share)	$ 3.37
Percentage of original number of shares subject to the option vesting	25.00%
Additional percentage of shares subject to the option vesting at the end of each successive three-month period	6.25%
Total intrinsic value of options exercised					$ 942,000	$ 768,000	$ 921,000
Total fair value of employee options vested					$ 3,700,000	$ 1,800,000	$ 1,300,000
Stock options granted (in shares)					1,747,495
Expense related to the restricted stock granted to non-employees	$ 1,700,000
Unrecognized compensation expense					$ 1,800,000
2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of purchase price of common stock owned by shareholder (as a percent)					10.00%
Percentage of fair value exercise price grant date of incentive stock options granted to 10% shareholder employees (as a percent)					110.00%
Award vesting period					4 years
Expected term					10 years
Stock incentive plan, reserved shares of common stock (in shares)							1,347,821
Stock incentive plan, shares remained available for future issuance (in shares)							1,586
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, annual increase in reserved shares of common stock (in shares)							1,102,362
Cliff for New Employee | 2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					1 year
Non-Employee Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, issued (in shares)						6,660
Unvested stock outstanding (in shares)					0
Expense related to the restricted stock granted to non-employees					$ 3,000	$ 45,000	$ 58,000
Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					4 years
Expected term					10 years
Expense related to the restricted stock granted to non-employees					$ 40,000	$ 0	$ 293,000
Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of shares authorized (in dollars per share)					$ 0.28
Option granted, weighted average grant date fair value (in dollars per share)					$ 1.09	$ 5.60	$ 8.68
Employee stock purchase plan issued during period (in shares)						5,000
Expense related to the restricted stock granted to non-employees					$ 3,300,000	$ 2,000,000	$ 1,600,000
Weighted average period unvested stock to be recognized					2 years 11 months 10 days
Non-Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term					10 years	10 years	10 years
Stock options granted (in shares)					0	0	0
Expense related to options granted to employees					$ 0	$ 168,000	$ 504,000
Non-Employee Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued to non-employees					0	0	0
A2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of shares authorized (in dollars per share)		$ 0.42	$ 0.31
Employee stock purchase plan issued during period (in shares)		68,111	20,760
Expense related to the restricted stock granted to non-employees					$ 0
ESOP authorized and issued in 2014 (in shares)								157,480
2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense related to the restricted stock granted to non-employees	$ 100,000
2014 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, reserved shares of common stock (in shares)					1,088,303		708,661
Stock incentive plan, annual increase in reserved shares as percentage of outstanding common stock (as a percent)				4.00%