Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	June 2019 Offering [Member]	September 2019 Offering [Member]	June 2018 Warrants [Member]	May 2020 Warrant Transaction [Member]	May 2020 Warrants [Member]	June 2019 Purchase Agreement [Member]	March 2018 PIPE [Member]	July 2020 Warrants [Member]	Common Stock [Member]	Common Stock [Member] June 2019 Offering [Member]	Common Stock [Member] September 2019 Offering [Member]	Common Stock [Member] June 2018 Warrants [Member]	Common Stock [Member] June 2019 Purchase Agreement [Member]	Common Stock [Member] March 2018 PIPE [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] June 2019 Offering [Member]	Additional Paid-In Capital [Member] September 2019 Offering [Member]	Additional Paid-In Capital [Member] June 2018 Warrants [Member]	Additional Paid-In Capital [Member] May 2020 Warrant Transaction [Member]	Additional Paid-In Capital [Member] May 2020 Warrants [Member]	Additional Paid-In Capital [Member] June 2019 Purchase Agreement [Member]	Additional Paid-In Capital [Member] March 2018 PIPE [Member]	Additional Paid-In Capital [Member] July 2020 Warrants [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Non-Controlling Interest [Member]
Stockholders Equity, Beginning Balance at Dec. 31, 2018	$ 12,815									$ 45						$ 191,136									$ (178,366)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2018										4,774,919
Issuance of shares related to employee stock purchase plan	8															8
Issuance of shares related to employee stock purchase plan, Shares										2,500
Stock-based compensation	422															422
Net (loss) income	(12,612)																								(12,612)
Stockholders Equity, Ending Balance at Mar. 31, 2019	633									$ 45						191,566									(190,978)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2019										4,777,419
Stockholders Equity, Beginning Balance at Dec. 31, 2018	12,815									$ 45						191,136									(178,366)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2018										4,774,919
Net (loss) income	(22,562)
Stockholders Equity, Ending Balance at Sep. 30, 2019	14,233									$ 49						214,423									(200,928)		$ 689
Stockholders Equity, Ending Balance, Shares at Sep. 30, 2019										8,646,149
Stockholders Equity, Beginning Balance at Dec. 31, 2018	12,815									$ 45						191,136									(178,366)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2018										4,774,919
Net (loss) income	(28,900)
Stockholders Equity, Ending Balance at Dec. 31, 2019	8,326									$ 49						214,826									(207,171)	$ 1	621
Stockholders Equity, Ending Balance, Shares at Dec. 31, 2019										8,646,149
Stockholders Equity, Beginning Balance at Mar. 31, 2019	633									$ 45						191,566									(190,978)
Stockholders Equity, Beginning Balance, Shares at Mar. 31, 2019										4,777,419
Issuance of shares							$ 3,303							$ 2								$ 3,301
Issuance of shares, Shares														1,489,575
Issuance of placement agent warrants		$ 198															$ 198
Issuance of shares related to the exercise of warrants		$ 5,269									$ 1						$ 5,268
Issuance of shares related to the exercise of warrants, Shares											1,053,745
Offering costs							$ (487)															$ (487)
Stock-based compensation	389															389
Net (loss) income	4,237																								4,237
Stockholders Equity, Ending Balance at Jun. 30, 2019	13,542									$ 48						200,235									(186,741)
Stockholders Equity, Ending Balance, Shares at Jun. 30, 2019										7,320,739
Issuance of shares related to employee stock purchase plan	10															10
Issuance of shares related to employee stock purchase plan, Shares										6,036
Issuance of shares related to employee stock option exercises	3															3
Issuance of shares related to employee stock option exercises, Shares										546
Reclassification of common stock warrant liability balance with exercise	7,016															7,016
Issuance of shares			$ 6,571									$ 1						$ 6,570
Issuance of shares, Shares												1,318,828
Issuance of placement agent warrants			326															326
Offering costs			$ (796)															$ (796)
Stock-based compensation	1,059															1,059
Unrealized losses on available-for-sale securities	(1)
Non-controlling interest contributions	689																										689
Net (loss) income	(14,187)																								(14,187)
Stockholders Equity, Ending Balance at Sep. 30, 2019	14,233									$ 49						214,423									(200,928)		689
Stockholders Equity, Ending Balance, Shares at Sep. 30, 2019										8,646,149
Stockholders Equity, Beginning Balance at Dec. 31, 2019	8,326									$ 49						214,826									(207,171)	1	621
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2019										8,646,149
Issuance of shares related to employee stock purchase plan	14															14
Issuance of shares related to employee stock purchase plan, Shares										7,946
Stock-based compensation	772															772
Unrealized losses on available-for-sale securities	(1)																									(1)
Non-controlling interest contributions	689																										689
Net (loss) income	2,423																								2,525		(102)
Stockholders Equity, Ending Balance at Mar. 31, 2020	12,223									$ 49						215,612									(204,646)		1,208
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2020										8,654,095
Stockholders Equity, Beginning Balance at Dec. 31, 2019	8,326									$ 49						214,826									(207,171)	$ 1	621
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2019										8,646,149
Unrealized losses on available-for-sale securities	(1)
Net (loss) income	(14,634)
Stockholders Equity, Ending Balance at Sep. 30, 2020	12,002									$ 51						231,954									(220,725)		722
Stockholders Equity, Ending Balance, Shares at Sep. 30, 2020										10,832,203
Stockholders Equity, Beginning Balance at Mar. 31, 2020	12,223									$ 49						215,612									(204,646)		1,208
Stockholders Equity, Beginning Balance, Shares at Mar. 31, 2020										8,654,095
Issuance of shares				$ 5,569									$ 1						$ 5,568
Issuance of shares, Shares													1,392,345
Issuance of investor warrants					$ 4,415															$ 4,415
Issuance of placement agent warrants						$ 215															$ 215
Stock-based compensation	595															595
Non-controlling interest contributions	493																										493
Net (loss) income	(9,893)																								(9,688)		(205)
Stockholders Equity, Ending Balance at Jun. 30, 2020	13,617									$ 50						226,405									(214,334)		1,496
Stockholders Equity, Ending Balance, Shares at Jun. 30, 2020										10,046,440
Issuance of shares related to employee stock purchase plan	37															37
Issuance of shares related to employee stock purchase plan, Shares										11,721
Issuance of shares								$ 2,444							$ 1								$ 2,443
Issuance of shares, Shares															641,416
Issuance of investor warrants									$ 2,059															$ 2,059
Issuance of placement agent warrants									$ 101															$ 101
Stock-based compensation	477															477
Shares of common stock issued at closing of ISI transaction	432															432
Shares of common stock issued at closing of ISI transaction, Shares										132,626
Net (loss) income	(7,165)																								(6,391)		(774)
Stockholders Equity, Ending Balance at Sep. 30, 2020	$ 12,002									$ 51						$ 231,954									$ (220,725)		$ 722
Stockholders Equity, Ending Balance, Shares at Sep. 30, 2020										10,832,203