Fair Value of Financial Assets and Liabilities - Derivative Instruments (Narrative) (Details) - USD ($)		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 08, 2016	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2016	Nov. 30, 2016
Derivatives And Fair Value [Line Items]
Transfers between fair value levels, in			$ 0		$ 0
Transfers between fair value levels, out			$ 0		$ 0
Remaining shares authorized for issuance			67,000,000	67,000,000	67,000,000
Derivative liability			$ 2,329,000	$ 2,443,000	$ 2,443,000
Common stock closing price			$ 4.30
Common Stock Issuance Agreement [Member]
Derivatives And Fair Value [Line Items]
Proceeds from issuance of private placement, gross				$ 9,000,000
Shares issued per agreements	85,346	75,020
Remaining shares authorized for issuance			28,684	28,684	28,684
Derivative liability	$ 2,300,000
Common stock closing price			$ 4.30	$ 4.40	$ 4.40
Dilutive Financing Derivative Liability [Member]
Derivatives And Fair Value [Line Items]
Derivative liability			$ 123,000	$ 126,000	$ 126,000
Dilutive Financing Derivative Liability [Member] | Common Stock Issuance Agreement [Member]
Derivatives And Fair Value [Line Items]
Derivative liability			123,000	126,000	126,000
November 2016 Warrant Derivative Liability [Member]
Derivatives And Fair Value [Line Items]
Derivative liability			$ 1,961,000	$ 2,043,000	$ 2,043,000
Common stock closing price			$ 4.30	$ 4.40	$ 4.40
Number of securities called by warrants						533,500
June 2016 Offering Liability [Member]
Derivatives And Fair Value [Line Items]
Derivative liability			$ 245,000	$ 274,000	$ 274,000
Common stock closing price			$ 4.30	$ 4.40	$ 4.40
Number of securities called by warrants		106,383