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Stockholders' Equity (Deficit) - Additional Information (Detail)							1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 09, 2019 shares	Jul. 08, 2019 $ / shares shares	Oct. 31, 2018 $ / shares shares	Oct. 01, 2016 d $ / shares shares	Mar. 18, 2016 d	Jun. 09, 2015 USD ($) shares	Jul. 31, 2019 shares	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) d Incentive_Plan $ / shares shares	Sep. 30, 2018 USD ($)	Mar. 26, 2019 shares	Dec. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants, exercise price \| $ / shares			$ 7.155
Preferred stock, par value \| $ / shares								$ 0.0001		$ 0.0001			$ 0.0001
Preferred stock, shares authorized								24,984,166		24,984,166			24,984,166
Number of stock incentive plans \| Incentive_Plan										2
Stock incentive plan expiration date										Aug. 31, 2015
Award authorized by board												800,000
Compensation costs associated \| $								$ 679,600	$ 103,904	$ 751,996	$ 311,712
Number of warrants								120,000		120,000
Warrants, expiration date										Oct. 01, 2021
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			700,000
Stock issued during theperiod share warrants										120,000
Accounting Standards Update 2017-01 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of ownership acquired	79.90%
Business combination number of shares issued or issuable	249,584
Bismarck [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business combination number of shares issued or issuable							249,584
Bismarck [Member] \| Accounting Standards Update 2017-01 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of ownership acquired	79.90%
Business combination number of shares issued or issuable	249,584
Note And Warrant Purchase Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants, exercise price \| $ / shares		$ 5.756						$ 12.00		$ 12.00
Number of warrants								65,625		65,625
Warrants, expiration date		Jul. 12, 2024								Jul. 21, 2021
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		196,135
Note And Warrant Purchase Agreement [Member] \| Second Amendment Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants, exercise price \| $ / shares		$ 5.756
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		196,135
2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board						450,000
Director Fees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs associated \| $										$ 675,000
Series AA-2 Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, par value \| $ / shares								$ 0.0001		$ 0.0001
Preferred stock, shares authorized								7,223,145		7,223,145
Series AA-2 Convertible Preferred Stock [Member] \| Penelope Mining LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of trading days \| d										20
Series AA-1 Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, par value \| $ / shares								$ 0.0001		$ 0.0001
Preferred stock, shares authorized								8,427,004		8,427,004
Preferred stock Liquidation preference accretion rate										8.00%
Minimum [Member] \| Series AA-2 Convertible Preferred Stock [Member] \| Penelope Mining LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing price of common stock \| $ / shares										$ 15.12
Notes Payable, Other Payables [Member] \| Epsilon Acquisitions, LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants, exercise price \| $ / shares				$ 3.52				$ 3.52		$ 3.52
Warrant Expiration Date										Oct. 01, 2021
Warrant right exercise price description										Warrant shall be the number determined by multiplying 120,000 by a fraction, (a) the numerator of which is the aggregate principal amount of advances that have been extended to the OME by Epsilon pursuant to the Restated Note Purchase Agreement on or after the date of the Warrant and prior to the date of such failure and (b) the denominator of which is $3.0 million.
Number of trading days \| d				75	75
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				120,000
Incentive Stock Options [Member] \| 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award authorized by board						450,000
Additional shares authorized for stock-based compensation										200,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock and warrants sold			700,000
Repurchases of common stock, shares			700,000
Purchase price of repurchased shares \| $ / shares			$ 7.155
Warrants, exercise price \| $ / shares			$ 7.155
Warrant Expiration Date			Nov. 02, 2023
Warrant right exercise price description			The warrants have an exercise price of $7.155 per share of common stock and are exercisable in accordance with their terms at any time on or before the close of business on November 2, 2023.
Common Stock [Member] \| Incentive Stock Options [Member] \| 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of incentive option granted										With respect to each grant of an ISO to a participant who is not a ten percent stockholder, the exercise price shall not be less than the fair market value of a share on the date the ISO is granted. With respect to each grant of an ISO to a participant who is a ten percent stockholder, the exercise price shall not be less than one hundred ten percent (110%) of the fair market value of a share on the date the ISO is granted.
Maximum aggregate number of Shares with respect to one or more Awards that may be granted to any one person during any calendar year						83,333
Maximum aggregate amount of cash that may be paid in cash to any person during any calendar year \| $						$ 2,000,000
Common Stock [Member] \| Incentive Stock Options [Member] \| Minimum [Member] \| 2015 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible employee threshold percentage										10.00%
Purchase price of common stock percentage										110.00%