Stock-Based Compensation - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2019 Milestone shares	Jun. 30, 2019 USD ($) Milestone shares	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Period Milestone $ / shares shares	Jun. 30, 2018 USD ($)	Apr. 28, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation | $		$ 922,000	$ 630,000	$ 1,956,000	$ 1,241,000
Cash proceeds from exercises of stock options | $				$ 105,000	$ 239,000
Weighted average fair value of stock options granted to employees | $ / shares				$ 5.50
Excess tax benefit from stock-based awards | $				$ 0
Performance Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of performance based award	221,600
Percentage of shares vested upon achievement of certain milestone	100.00%
Number of milestones to be achieve | Milestone	3
Number of milestones deemed as achievable | Milestone		3		3
Milestone achievement period	4 years
Stock-based compensation | $		$ 190,000		$ 392,000
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance						1,527,770
Additional number of shares of common stock reserved for issuance		4,832,334		4,832,334
Common stock reserved for issuance, description				Initially, a total of 1,527,770 shares of the Company’s common stock were reserved for issuance pursuant to the 2014 Plan, which number is also the limit on shares of common stock available for awards of incentive stock options. The number of shares available for issuance under the 2014 Plan will, unless otherwise determined by the Company’s Board of Directors or the Compensation Committee, be automatically increased on January 1st of each year commencing on January 1, 2016 and ending on (and including) January 1, 2024, in an amount equal to 3.5% of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year.
Percentage of common stock outstanding to increase shares reserved for issuance				3.50%
2014 ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance						458,331
Additional number of shares of common stock reserved for issuance		1,380,666		1,380,666
Common stock reserved for issuance, description				The number of shares available for issuance under the ESPP will, unless otherwise determined by the Company’s Board of Directors or the Compensation Committee, be automatically increased on January 1st of each year commencing on January 1, 2016 and ending on (and including) January 1, 2024, in an amount equal to 1% of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year.
Percentage of common stock outstanding to increase shares reserved for issuance				1.00%
Duration of employee stock purchase plan as determined by the compensation committee				24 months
Duration for offering period, employee stock purchase plan				6 months
Employee stock purchase plan, number of purchase periods | Period				4
Maximum duration for purchase under employee stock purchase plan				1 year
Maximum duration of employee stock purchase plan				27 months
Percentage of purchase of common stock				85.00%
Percentage of common stock on the date of purchase				85.00%