Stock-Based Compensation (Detail)	6 Months Ended
	Jun. 30, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Options granted	1,413,904
Weighted Average Exercise Price Per share, End of year | $ / shares	$ 2.04
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning of year	175,046
Shares Available For Grant, Options granted	0
Shares Available For Grant, Options forfeited	0
Shares Available For Grant, Options expired	27,744
Shares Available for Grant, End of year	202,290
Number of Shares, Beginning of Year	514,772
Number of Shares, Options granted	0
Number Of Shares, Options forfeited	0
Number Of Shares, Options expired	(27,744)
Number of Shares, End of Year	487,528
Number of Shares, Total vested and expected to vest shares (options)	487,528
Number of Shares, Total vested shares (options)	237,520
Weighted Average Exercise Price Per share, Beginning of year | $ / shares	$ 2.77
Weighted Average Exercise Price Per Share, Options granted | $ / shares	0
Weighted Average Exercise Price Per Share, Options forfeited | $ / shares	0
Weighted Average Exercise Price Per Share, Options expired | $ / shares	15.80
Weighted Average Exercise Price Per share, End of year | $ / shares	2.04
Weighted Average Exercise Price Per Share, Total vested and expected to vest shares (options) | $ / shares	2.04
Weighted Average Exercise Price Per Share, Total vested shares (options) | $ / shares	$ 2.45