Stockholders' Equity (Detail) - USD ($)	1 Months Ended				2 Months Ended	6 Months Ended	9 Months Ended
	Aug. 31, 2017	Jul. 31, 2017	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Maximum proceeds	$ 150,000,000			$ 100,000,000
No. of Common Shares Issued (shares)		3,243,882			9,314,250	10,890,915
Proceeds from issuance of common stock		$ 23,745,000			$ 90,221,000	$ 73,869,000	$ 113,966,000	$ 73,869,000
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Outstanding (shares)			20
Issued in conversion (shares)			40,000
Dividends in arrears			$ 6,000