CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Revenue		$ 1,402	$ 22,378	$ 2,759
Revenue, Product and Service [Extensible List]			nxtc:RelatedPartyMember
Operating expenses:
Research and development	$ 11,130	7,643	$ 21,708	14,156
General and administrative	4,671	2,714	8,259	4,373
Total operating expenses	15,801	10,357	29,967	18,529
Loss from operations	(15,801)	(8,955)	(7,589)	(15,770)
Other income, net	1,293	734	2,814	1,394
Net loss	$ (14,508)	$ (8,221)	$ (4,775)	$ (14,376)
Loss per share
Net loss per common share—basic and diluted (in dollars per share)	$ (0.53)	$ (0.61)	$ (0.17)	$ (1.92)
Shares used in the calculation of loss per share
Weighted average number of common shares —basic and diluted (in shares)	27,518,129	13,498,393	27,512,528	7,472,298
Comprehensive Loss:
Net loss	$ (14,508)	$ (8,221)	$ (4,775)	$ (14,376)
Unrealized gain on marketable securities	2,478		1,935
Total comprehensive loss	$ (12,030)	$ (8,221)	$ (2,840)	$ (14,376)