Stock Benefit Plans and Equity Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended
	Mar. 08, 2018	Mar. 31, 2017	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Oct. 25, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant outstanding			26,885,361				26,885,361
Stock-based compensation							$ 3,963	$ 1,767
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			3,657,000				3,657,000
Proceeds from exercise of warrant			$ 200				$ 200	$ 900
Number of warrants exercised			100,000				100,000	400,000
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			13,860,851				13,860,851
Proceeds from exercise of warrant							$ 500
Number of warrants exercised							100,000	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
Warrants term			7 years				7 years
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of preferred shares converted to common stock				1,858,000		637,000
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of preferred shares converted							3,715	1,274
Number of preferred shares outstanding for being conversion			328				328
Series A Convertible Preferred Stock | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of preferred shares converted to common stock							1,857,586	636,997
Number of preferred shares outstanding for being conversion to common stock			164,087				164,087
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 | 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 | Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares issued		15,245
Shares issued price per share		$ 1,000
2017 Private Placement | Series A Convertible Preferred Stock | Common 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	$ 800
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]
Preferred stock, shares issued	45,200
Shares issued price per share	$ 1,000
2018 Private Placement | Series A Convertible Preferred Stock | Common 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									60,000
Two Thousand Seventeen Distributor Inducement Plan | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)			300,000				300,000
Common stock issued							17,000
Stock-based compensation			$ 100		$ 100		$ 200	$ 100
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 | Common Stock | Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share authorized grant of warrants			2,300,000				2,300,000		3,000,000
Common stock issued							0
Issuance of shares granted to distributors was vested							0