CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Revenue	$ 1,402		$ 2,759
Type of Revenue [Extensible List]			nxtc:RelatedPartyMember
Operating expenses:
Research and development	7,643	$ 4,434	$ 14,156	$ 8,644
General and administrative	2,714	866	4,373	1,665
Total operating expenses	10,357	5,300	18,529	10,309
Loss from operations	(8,955)	(5,300)	(15,770)	(10,309)
Other income, net	734	69	1,394	82
Net loss	$ (8,221)	$ (5,231)	$ (14,376)	$ (10,227)
Net loss per share attributable to common stockholders—basic and diluted (in dollars per share)	$ (0.61)	$ (3.82)	$ (1.92)	$ (7.47)
Weighted average common shares outstanding—basic and diluted (in shares)	13,498,393	1,369,212	7,472,298	1,369,212