Annual report pursuant to Section 13 and 15(d)

Stock Plans - Schedule of Restricted Stock Activity (Detail)

v3.19.1
Stock Plans - Schedule of Restricted Stock Activity (Detail) - 2014 Plan Stock Options/Stock Issuance Plan and 2017 Stock Incentive Plan [Member] - Restricted Stock Awards [Member]
12 Months Ended
Dec. 31, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares, Unvested, Beginning Balance | shares 147,456
Shares, Forfeited | shares (1,975)
Shares, Vested | shares (73,273)
Shares, Unvested, Ending Balance | shares 72,208
Weighted Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares $ 6.30
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 7.50
Weighted Average Grant Date Fair Value, Vested | $ / shares 5.32
Weighted Average Grant Date Fair Value, Unvested, Ending Balance | $ / shares $ 7.26