Preferred Stock, Common Stock and Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($)									1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended
	Mar. 10, 2017	Mar. 03, 2017	Feb. 22, 2017	Dec. 15, 2016	Aug. 03, 2016	Aug. 03, 2016	Jul. 25, 2016	Apr. 15, 2016	Feb. 28, 2017	Mar. 31, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Mar. 15, 2017
Sale Of Stock [Line Items]
Common stock, shares outstanding												12,350,360	7,201,774
Shareholders voting power description												Each share of common stock is entitled to one vote. The holders of the common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors of the Company.
Dividends declared on common stock												$ 0
Common stock, shares issued												12,350,360	7,201,774
Warrant exercise price per share												$ 3.29	$ 16.73
Proceeds from issuance of common stock, net												$ 354,855	$ 5,031,184
Scenario Forecast [Member]
Sale Of Stock [Line Items]
Gross proceeds from public offering of common stock										$ 8,000,000
Subsequent Event [Member]
Sale Of Stock [Line Items]
Issuance of common stock from At-The-Market offering, shares net		362,068
Value of shares sold in prior twelve months	$ 4,800,000
July 2016 Financing [Member]
Sale Of Stock [Line Items]
Common stock, shares issued							1,804,512
Purchase price of common stock							$ 2.49375
Aggregate gross proceeds from sale of common stock and warrants							$ 4,500,000
Aggregate net proceeds from sale of common stock and warrants							$ 4,000,000
July 2016 Financing [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Warrant exercise price per share									$ 2.41
Common stock shares issued upon conversion of warrants									211,860
July 2016 Financing [Member] | Liability [Member] | Subsequent Event [Member] | Warrants to purchase common stock [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock														2,449,129
July Warrants [Member]
Sale Of Stock [Line Items]
Warrants exercisable, stock issued							0.75
Unregistered warrants to purchase of common stock							1,353,384
Warrant exercise price per share							$ 2.41
Warrants expiration date							Jan. 25, 2022
July Wainwright Warrants [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock							90,226
Warrant exercise price per share							$ 3.1172
Warrants expiration date							Jul. 21, 2021
August 2016 Financing [Member]
Sale Of Stock [Line Items]
Common stock, shares issued					3,244,120	3,244,120
Purchase price of common stock					$ 3.0825	$ 3.0825
Aggregate gross proceeds from sale of common stock and warrants						$ 10,000,000
Aggregate net proceeds from sale of common stock and warrants						$ 9,200,000
August Warrants [Member]
Sale Of Stock [Line Items]
Warrants exercisable, stock issued					0.5	0.5
Unregistered warrants to purchase of common stock					1,622,060	1,622,060
Warrant exercise price per share					$ 3.03	$ 3.03
Warrants expiration date						Feb. 03, 2022
August Wainwright Warrants [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock					162,206	162,206
Warrant exercise price per share					$ 3.853125	$ 3.853125
Warrants expiration date						Jul. 29, 2021
2016 Financings [Member]
Sale Of Stock [Line Items]
Common stock, shares issued					5,048,632	5,048,632					5,048,632
Aggregate gross proceeds from sale of common stock and warrants					$ 14,500,000						$ 14,500,000
2016 Financings [Member] | Warrants to purchase common stock [Member] | Maximum [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock											2,975,444
2016 Financings [Member] | Warrant Liability [Member]
Sale Of Stock [Line Items]
Total initial fair value of warrants issued												$ 4,899,459
Warrant Amendments [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock				252,432
Amendment Date				Dec. 15, 2016
Reclassification of warrant liability to Additional Paid-in Capital				$ 207,000
Underwritten Public Offering [Member] | Scenario Forecast [Member]
Sale Of Stock [Line Items]
Purchase price of common stock										$ 2.90
Issuance of common stock from At-The-Market offering, shares net										2,775,861
Gross proceeds from public offering of common stock										$ 8,000,000
Proceeds from issuance of common stock, net										$ 7,100,000
Underwritten Public Offering [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Issuance of common stock from At-The-Market offering, shares net			2,413,793
Gross proceeds from public offering of common stock		$ 8,000,000
FBR Sales Agreement [Member]
Sale Of Stock [Line Items]
Common stock, shares issued												56,000
Proceeds from issuance of common stock, net												$ 296,000
Common stock, shares issuable								649,074
Common stock, weighted average price per share												$ 5.45
FBR Sales Agreement [Member] | Maximum [Member]
Sale Of Stock [Line Items]
Common stock, value of shares issuable												$ 8,600,000
Entity public float												$ 75,000,000
FBR Sales Agreement [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Entity public float	$ 40,100,000
Entity public float, common stock shares	12,846,511
Common stock, closing price	$ 3.12
FBR Sales Agreement [Member] | Subsequent Event [Member] | Maximum [Member]
Sale Of Stock [Line Items]
Common stock, value of shares issuable	$ 20,000,000