Shareholders' Equity - Summary of Restricted Stock Unit Activity (Detail)	6 Months Ended
	Jun. 30, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of Shares, Ending Balance	150,380
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Number of Shares, Beginning Balance	119,606
Granted, Number of Shares	61,409
Vested, Number of Shares	(30,635)
Unvested, Number of Shares, Ending Balance	150,380
Expected to vest, Number of Shares, Ending Balance	134,077
Unvested, Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 5.60
Granted, Weighted Average Grant Date Fair Value | $ / shares	4.89
Vested, Weighted Average Grant Date Fair Value | $ / shares	5.76
Unvested, Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	5.28
Expected to vest, Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 5.28