CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($)	Total	Series A, B, C & C-1 Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Redeemable Convertible Preferred Stock and Preferred Stock Dividends to Common Stock	Redeemable Convertible Preferred Stock and Preferred Stock Dividends to Common Stock Series A, B, C & C-1 Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock and Preferred Stock Dividends to Common Stock Common Stock	Redeemable Convertible Preferred Stock and Preferred Stock Dividends to Common Stock Additional Paid-In Capital	Convertible Notes Payable and Accrued Interest to Common Stock	Convertible Notes Payable and Accrued Interest to Common Stock Common Stock	Convertible Notes Payable and Accrued Interest to Common Stock Additional Paid-In Capital
Beginning Balance (in shares) at Dec. 31, 2017			585,262
Beginning Balance at Dec. 31, 2017	$ (59,936,000)		$ 6,000	$ 0	$ 0	$ (59,942,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	(3,240,000)			(207,000)		(3,033,000)
Stock based compensation	190,000			190,000
Issuance of common stock through exercise of stock option (in shares)			1,438
Issuance of common stock through exercise of stock option	17,000			17,000
Net income (loss)	527,000					527,000
Ending Balance (in shares) at Mar. 31, 2018			586,700
Ending Balance at Mar. 31, 2018	(59,708,000)		$ 6,000	0	0	(59,714,000)
Beginning Balance (in shares) at Dec. 31, 2017		1,256,466
Beginning Balance at Dec. 31, 2017		$ 52,354,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value		$ 3,240,000
Ending Balance (in shares) at Mar. 31, 2018		1,256,466
Ending Balance at Mar. 31, 2018		$ 55,594,000
Beginning Balance (in shares) at Dec. 31, 2017			585,262
Beginning Balance at Dec. 31, 2017	(59,936,000)		$ 6,000	0	0	(59,942,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on available-for-sale marketable securities	0
Net income (loss)	(5,566,000)
Ending Balance (in shares) at Sep. 30, 2018			587,563
Ending Balance at Sep. 30, 2018	(67,296,000)		$ 6,000	0	0	(67,302,000)
Beginning Balance (in shares) at Dec. 31, 2017		1,256,466
Beginning Balance at Dec. 31, 2017		$ 52,354,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Shares converted	0
Reduction of redeemable convertible preferred stock to redemption value	5,041,000
Ending Balance (in shares) at Sep. 30, 2018		1,256,466
Ending Balance at Sep. 30, 2018		$ 57,425,000
Beginning Balance (in shares) at Mar. 31, 2018			586,700
Beginning Balance at Mar. 31, 2018	(59,708,000)		$ 6,000	0	0	(59,714,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	(865,000)			(175,000)		(690,000)
Stock based compensation	175,000			175,000
Net income (loss)	(3,552,000)					(3,552,000)
Ending Balance (in shares) at Jun. 30, 2018			586,700
Ending Balance at Jun. 30, 2018	(63,950,000)		$ 6,000	0	0	(63,956,000)
Beginning Balance (in shares) at Mar. 31, 2018		1,256,466
Beginning Balance at Mar. 31, 2018		$ 55,594,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value		$ 865,000
Ending Balance (in shares) at Jun. 30, 2018		1,256,466
Ending Balance at Jun. 30, 2018		$ 56,459,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	(966,000)			(161,000)		(805,000)
Stock based compensation	151,000			151,000
Issuance of common stock through exercise of stock option (in shares)			863
Issuance of common stock through exercise of stock option	10,000			10,000
Unrealized loss on available-for-sale marketable securities	0
Net income (loss)	(2,541,000)					(2,541,000)
Ending Balance (in shares) at Sep. 30, 2018			587,563
Ending Balance at Sep. 30, 2018	$ (67,296,000)		$ 6,000	0	0	(67,302,000)
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value		$ 966,000
Ending Balance (in shares) at Sep. 30, 2018		1,256,466
Ending Balance at Sep. 30, 2018		$ 57,425,000
Beginning Balance (in shares) at Dec. 31, 2018	589,001		589,001
Beginning Balance at Dec. 31, 2018	$ (71,618,000)		$ 6,000	0	0	(71,624,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reduction of redeemable convertible preferred stock to redemption value	10,521,000					10,521,000
Stock based compensation	384,000			384,000
Net income (loss)	(4,580,000)					(4,580,000)
Ending Balance (in shares) at Mar. 31, 2019			589,001
Ending Balance at Mar. 31, 2019	$ (65,293,000)		$ 6,000	384,000	0	(65,683,000)
Beginning Balance (in shares) at Dec. 31, 2018	1,256,466	1,256,466
Beginning Balance at Dec. 31, 2018	$ 58,290,000	$ 58,290,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Reduction of redeemable convertible preferred stock to redemption value		$ (10,521,000)
Ending Balance (in shares) at Mar. 31, 2019		1,256,466
Ending Balance at Mar. 31, 2019		$ 47,769,000
Beginning Balance (in shares) at Dec. 31, 2018	589,001		589,001
Beginning Balance at Dec. 31, 2018	$ (71,618,000)		$ 6,000	0	0	(71,624,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on available-for-sale marketable securities	(11,000)
Net income (loss)	$ (13,015,000)
Ending Balance (in shares) at Sep. 30, 2019	7,810,680		7,810,680
Ending Balance at Sep. 30, 2019	$ 18,225,000		$ 78,000	92,276,000	(11,000)	(74,118,000)
Beginning Balance (in shares) at Dec. 31, 2018	1,256,466	1,256,466
Beginning Balance at Dec. 31, 2018	$ 58,290,000	$ 58,290,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Shares converted	(48,016,000)
Reduction of redeemable convertible preferred stock to redemption value	$ (10,377,000)
Ending Balance (in shares) at Sep. 30, 2019	0	0
Ending Balance at Sep. 30, 2019	$ 0	$ 0
Beginning Balance (in shares) at Mar. 31, 2019			589,001
Beginning Balance at Mar. 31, 2019	(65,293,000)		$ 6,000	384,000	0	(65,683,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	(165,000)			(165,000)
Stock based compensation	299,000			299,000
Net income (loss)	(3,654,000)					(3,654,000)
Ending Balance (in shares) at Jun. 30, 2019			589,001
Ending Balance at Jun. 30, 2019	(68,813,000)		$ 6,000	518,000	0	(69,337,000)
Beginning Balance (in shares) at Mar. 31, 2019		1,256,466
Beginning Balance at Mar. 31, 2019		$ 47,769,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value		$ 165,000
Ending Balance (in shares) at Jun. 30, 2019		1,256,466
Ending Balance at Jun. 30, 2019		$ 47,934,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of redeemable convertible preferred stock to redemption value	(82,000)			(82,000)
Conversion of securities (in shares)									2,783,951			1,069,740
Conversion of securities							$ 48,016,000		$ 28,000	$ 47,988,000	$ 5,092,000	$ 10,000	$ 5,082,000
Common stock issued in recapitalization (in shares)			3,367,988
Common stock issued in recapitalization	36,093,000		$ 34,000	36,059,000
Stock based compensation	324,000			324,000
Reclassification of warrant liability to equity	1,511,000			1,511,000
Common stock warrants issued in connection with the research and development funding liability	876,000			876,000
Unrealized loss on available-for-sale marketable securities	(11,000)				(11,000)
Net income (loss)	$ (4,781,000)					(4,781,000)
Ending Balance (in shares) at Sep. 30, 2019	7,810,680		7,810,680
Ending Balance at Sep. 30, 2019	$ 18,225,000		$ 78,000	$ 92,276,000	$ (11,000)	$ (74,118,000)
Increase (Decrease) in Temporary Equity [Roll Forward]
Shares converted (in shares)								(1,256,466)
Shares converted								$ (48,016,000)
Accretion of redeemable convertible preferred stock to redemption value		$ 82,000
Ending Balance (in shares) at Sep. 30, 2019	0	0
Ending Balance at Sep. 30, 2019	$ 0	$ 0