Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common stock	Additional paid-in Capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Balance at Dec. 31, 2016	$ 36,410		$ 1	$ 111,691	$ 25	$ (75,307)
Balance (in shares) at Dec. 31, 2016			11,951,866
Increase (Decrease) in Stockholders' Equity
Issuance of common and preferred shares in equity offerings, net of transaction costs	173,805			173,805
Issuance of common and preferred shares in equity offerings, net of transaction costs (in shares)		1,969,797	2,275,768
Compensation expense related to stock options for services	3,254			3,254
Unrealized gain (loss) on marketable securities	(56)				(56)
Net loss	(31,154)					(31,154)
Balance at Dec. 31, 2017	182,259		$ 1	288,750	(31)	(106,461)
Balance (in shares) at Dec. 31, 2017		1,969,797	14,227,634
Increase (Decrease) in Stockholders' Equity
Issuance of common shares in equity offering, excluding to related parties, net of transaction costs	311,825		$ 1	311,824
Issuance of common shares in equity offering, excluding to related parties, net of transaction costs (in shares)			1,079,580
Sale of common shares to related parties and exercise of common stock options, net of transaction cost	2,510			2,510
Sale of common shares to related parties and exercise of common stock options, net of transaction cost ( in shares)			101,809
Compensation expense related to stock options for services	13,489			13,489
Unrealized gain (loss) on marketable securities	(288)				(288)
Net loss	(32,811)					(32,811)
Balance at Dec. 31, 2018	$ 476,984		$ 2	616,573	(319)	(139,272)
Balance (in shares) at Dec. 31, 2018	15,409,023	1,969,797	15,409,023
Increase (Decrease) in Stockholders' Equity
Sale of common shares to related parties and exercise of common stock options, net of transaction cost	$ 235			235
Sale of common shares to related parties and exercise of common stock options, net of transaction cost ( in shares)			20,131
Compensation expense related to stock options for services	22,759			22,759
Unrealized gain (loss) on marketable securities	535				535
Net loss	(83,948)					(83,948)
Balance at Dec. 31, 2019	$ 416,565		$ 2	$ 639,567	$ 216	$ (223,220)
Balance (in shares) at Dec. 31, 2019	15,429,154	1,969,797	15,429,154