Stock Benefit Plans and Equity Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
	Aug. 02, 2019	Mar. 08, 2018	Mar. 31, 2017	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Oct. 25, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net proceeds from offering								$ 2,073	$ 51,554
Warrant outstanding				26,739,483				26,739,483
Stock-based compensation								$ 7,566	3,442
2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants				$ 2.00				$ 2.00
Warrant outstanding				3,357,000				3,357,000
Proceeds from exercise of warrant				$ 600				$ 800	$ 4,000
Number of warrants exercised				300,000		0		400,000	1,900,000
2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants				$ 2.50				$ 2.50
Warrant outstanding				148,554				148,554
2018 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)				1,800,000				1,800,000
Exercise price of warrants				$ 3.50				$ 3.50
Warrant outstanding				13,827,473				13,827,473
Proceeds from exercise of warrant								$ 600
Number of warrants exercised								200,000	0
Warrants term				5 years				5 years
Squadron Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)				4,838,710				4,838,710			845,000
Exercise price of warrants				$ 2.17				$ 2.17			$ 3.15
Warrant outstanding				5,683,710				5,683,710
Warrants term				7 years				7 years
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of preferred shares converted								3,909	1,274
Number of preferred shares outstanding for being conversion				135				135
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued				12,535,000
Number of preferred shares converted to common stock				97,000	1,858,000		637,000
Common Stock | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of preferred shares converted to common stock								1,954,335	636,997
Number of preferred shares outstanding for being conversion to common stock				67,338				67,338
August 2019 Offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net proceeds from offering	$ 54,000
August 2019 Offering | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued	12,535,000
Shares issued price per share	$ 4.60
Shares issued of underwriters option to purchase additional shares	1,635,000
2017 Private Placement | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants				$ 2.00				$ 2.00
2017 Private Placement | 2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants				$ 2.50				$ 2.50
2017 Private Placement | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued price per share			$ 1,000
Preferred stock, shares issued			15,245
2017 Private Placement | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock upon securities purchase agreement			1,809,628
Common stock purchase price per share			$ 2.00
2017 Private Placement | Common Stock | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock convertible to common stock			7,622,372
2018 Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants		$ 3.50
Proceeds from exercise of warrant									$ 4,800
Warrant expiration period		5 years
Aggregate gross proceeds for private placement		$ 45,200
2018 Private Placement | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of warrants						$ 2.00			$ 2.00
Warrant outstanding						2,400,000			2,400,000
Proceeds from exercise of warrant									$ 4,800
2018 Private Placement | 2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant outstanding				148,554				148,554
Proceeds from exercise of warrant								$ 100	$ 700
Number of warrants exercised								18,864	304,182
2018 Private Placement | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued price per share		$ 1,000
Preferred stock, shares issued		45,200
2018 Private Placement | Common Stock | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock convertible to common stock		14,349,236
Maximum | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beneficial ownership limitation percentage								4.99%
Beneficial ownership, limitation option, percentage								9.99%
Beneficial ownership limitation notification period								61 days
Maximum | 2018 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beneficial ownership limitation percentage								4.99%
Beneficial ownership, limitation option, percentage								9.99%
Beneficial ownership limitation notification period								61 days
Maximum | 2017 Private Placement | 2017 Banker Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)				471,600				471,600
Maximum | 2017 Private Placement | Common Stock | 2017 Common Stock Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)				9,432,000				9,432,000
Maximum | 2018 Private Placement | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)		12,196,851
2016 Equity Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant												500,000
2016 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant												1,250,000
Two Thousand Seventeen Distributor Inducement Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant										75,000
Number of shares earned and issued										75,000
Two Thousand Seventeen Distributor Inducement Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued								92,000
Number of warrants issued (in shares)				200,000				200,000
Stock-based compensation				$ 100		$ 100		$ 300	$ 200
Number of warrants available to be granted										50,000
Two Thousand Seventeen Distributor Inducement Plan | Common Stock | Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share authorized grant of warrants										1,000,000
2017 Development Services Plan | Restricted Common Stock | Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share of restricted common stock granted								2,400,000
2017 Development Services Plan | Common Stock | Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued								0
Share authorized grant of warrants										3,000,000
Issuance of shares granted to distributors was vested								0