Net Loss per Share - Additional Information (Detail) - shares		1 Months Ended					12 Months Ended
	Jun. 04, 2019	Dec. 31, 2019	May 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock units vested shares					83,791
Common Stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock units vested shares		36,666	74,166				110,832	83,791
Restricted Stock Units [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock units, vested		36,666	74,166
Restricted Stock Units [Member] | 2014 Equity Incentive Plan [Member] | Executive Officers [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock units, vested		36,666	74,166
Restricted stock units, approved and granted				215,000		83,791
Restricted Stock Units [Member] | 2014 Equity Incentive Plan [Member] | Director [Member] | Share-based Payment Arrangement, Nonemployee [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Restricted stock units, vested							0
Restricted stock units, approved and granted	24,000						24,000
Employee Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive common stock equivalents							4,450,517	4,004,422	3,492,141
Restricted Stock Units [Member] | Executive Officers [Member] | Share-based Payment Arrangement, Employee [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive common stock equivalents							104,168
Restricted Stock Units [Member] | 2014 Equity Incentive Plan [Member] | Director [Member] | Share-based Payment Arrangement, Nonemployee [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive common stock equivalents	24,000