Stockholders' Equity - Additional Information (Detail) - USD ($)			1 Months Ended				2 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2019	Jul. 18, 2019	Nov. 30, 2021	Dec. 31, 2020	Feb. 29, 2020	Feb. 28, 2019	Feb. 15, 2022	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Authorized capital stock									520,000,000
Common stock, par value				$ 0.0001					$ 0.0001	$ 0.0001
Common stock, shares authorized				500,000,000					500,000,000	500,000,000
Preferred stock, par value									$ 0.0001
Preferred stock, shares authorized									20,000,000
Preferred stock, shares outstanding				0					0	0
Stock option granted description terms									the exercise price of an option granted to a 10% shareholder cannot be less than 110% of the estimated fair value of the shares on the date of grant. The estimated fair value is generally equal to the closing market price of the Company’s common stock on the measurement date. Options granted generally vest over four years and expire in seven to ten years.
Ownership percent									10.00%
Shares of common stock, reserved for issuance									20,971,553
Additional shares of common stock, reserved for issuance													1,500,000
Common stock, shares exercised									246,867	268,938	347,716
Option intrinsic value, exercised									$ 800,000	$ 1,000,000.0	$ 3,800,000
Net tax benefits related to exercised options									0
Estimated fair value of stock option, vested									26,600,000	29,400,000	31,600,000
Stock-based compensation expense									$ 53,865,000	$ 51,351,000	$ 51,696,000
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value per share									$ 16.42	$ 12.19	$ 27.04
Estimated fair value, vested in period									$ 27,100,000	$ 23,600,000	$ 13,800,000
Unrecognized stock-based compensation expense									$ 75,700,000
Unrecognized stock-based compensation weighted average recognition period									2 years 9 months 18 days
Aggregate intrinsic value									$ 88,100,000
Restricted stock units, settled									1,553,893	1,218,945
RSU settlements, net of shares withheld, shares									154,341	276,822
Restricted stock units withheld for tax obligations									61,385	106,459
Restricted stock units withheld for tax obligations, value									$ 1,200,000	$ 1,500,000
Restricted Stock Units (RSUs) | From Date Of Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, vesting period									4 years
Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, vesting period									4 years
Vested and Unvested Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation weighted average recognition period									2 years 6 months
Stock options, issued												275,000
Unrecognized stock-based compensation									$ 41,900,000
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in EIP/ESPP, subject to other limitations									5.00%
Shares of common stock, reserved for issuance									16,086,987
Shares of common stock, reserved for issuance									4,018,597
Outstanding options and RSUs									12,068,390
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock, reserved for issuance									4,022,184
Shares of common stock, reserved for issuance									1,278,379
Outstanding options and RSUs									2,743,805
Additional shares of common stock, reserved for issuance														1,500,000
2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of employees purchase price of common stock									85.00%
Shares of common stock, reserved for issuance									862,382
Unrecognized stock-based compensation expense									$ 600,000
Employee stock purchase plan effective date									Oct. 15, 2014
Employee stock purchase plan description									(i) the beginning of a 12-month offering period, or (ii) at the end of one of the two related 6-month purchase periods
Employee stock purchase plan offering commenced start date									Jun. 01, 2016
Stock-based compensation expense									$ 1,700,000	$ 1,800,000	$ 1,300,000
Shares purchased									319,190	282,514	139,466
Aggregate number of shares authorized									1,817,511
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of employees purchase price of common stock									100.00%
Minimum | 10% Shareholder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of employees purchase price of common stock									110.00%
Minimum | Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation award expiration period									7 years
Maximum | Employees And Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation award expiration period									10 years
Maximum | 2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in EIP/ESPP, subject to other limitations									1.00%
Stock may be issued or transferred, value									$ 25,000
Maximum increase in number of shares available for issuance									230,769
Underwritten Public Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares issued	6,871,727			5,102,041				12,633,039
Shares issued, price per share	$ 15.28			$ 24.50				$ 11.32		$ 24.50
Proceeds from sale of common stock, gross	$ 150,000,000.0			$ 175,000,000.0				$ 201,800,000
Proceeds from sale of common stock, net	$ 140,700,000			$ 164,300,000				$ 189,300,000
Warrants outstanding									2,888,526
Option price to purchase shares								$ 11.32
Underwritten Public Offering | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional shares of our common stock								2,325,000
Underwritten Public Offering | Warrant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of warrants issued	2,945,026			2,040,816				2,866,961		2,040,816
Warrant, price per share	$ 15.2799			$ 24.4999				$ 11.3199		$ 24.4999
Number of securities called by each warrant		1
Warrants, exercise price		$ 0.0001
Warrants, term		7 years
Maximum ownership Percentage		9.99%
Underwritten Public Offering | Warrant | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Prior notice period		61 days
Underwritten Public Offering | Warrant | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum ownership Percentage		19.99%
At The Market Offering | Cowen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares issued							1,319,878		6,240,601	4,785,514
Proceeds from sale of common stock, gross							$ 21,000,000.0		$ 101,300,000	$ 69,900,000
Proceeds from sale of common stock, net							$ 20,500,000		$ 98,900,000	$ 68,000,000.0
Common stock average price							$ 15.88		$ 16.23	$ 14.60
Common stock value available to be sold							$ 57,400,000		$ 78,300,000
At The Market Offering | Maximum | Cowen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock aggregate offering price			$ 100,000,000.0		$ 100,000,000.0	$ 100,000,000.0
Percentage of commission to be paid on gross sales proceeds of common stock sold			3.00%		3.00%	3.00%