Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Millions	Aug. 01, 2016 USD ($) $ / shares shares
Stockholders Equity [Line Items]
Private placement, share lock-up period	2 years
Maximum [Member]
Stockholders Equity [Line Items]
Equity position under stock purchase agreement	19.90%
Stock Purchase Agreement with AnGes, MG, Inc in Private Placement [Member]
Stockholders Equity [Line Items]
Private placement, shares | shares	1,841,420
Private placement, price per share | $ / shares	$ 4.24
Private placement, gross proceeds | $	$ 7.8
Private placement, closing date	Aug. 02, 2016