Collaboration Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		7 Months Ended	12 Months Ended	34 Months Ended
	Feb. 28, 2018 USD ($)	Aug. 31, 2017 USD ($) employee $ / shares shares	Jun. 30, 2019 USD ($) shares	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) shares	Jun. 30, 2018 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue			$ 30,345	$ 24,999	$ 58,033	$ 48,084
Estimated deferred revenue recognized within one year			6,033		6,033					$ 9,890
Collaborative Arrangement | Celgene Corporation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue			3,100		4,400	200
Proceeds from collaborators			0		$ 200
Collaborative agreement period					1 year
Maximum success-based milestone payments	$ 19,000
Collaborative Arrangement | Celgene Corporation | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum success-based milestone payments	24,800
Collaborative Arrangement | Celgene Corporation | Upfront Payment Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement upfront payment	$ 5,800								$ 2,100
Collaborative Arrangement | Merck Sharp & Dohme Corp.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue				500		1,400
Collaborative Arrangement | Merck Sharp & Dohme Corp. | Upfront Payment Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue								$ 8,500
Proceeds from collaborators							$ 3,900	$ 12,000
Collaborative Arrangement | Lam Research Corporation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum amount of royalties payable (ratio)		3
Maximum number of employees | employee		10
Exercise price of warrants | $ / shares		$ 16.75
Issued warrants, value		$ 6,700
Revenue			4,400	4,000	$ 9,200	8,200
Proceeds from collaborators			5,500	7,900	8,200	11,400
Deferred revenue recorded under collaboration agreement			1,000		1,000
Estimated deferred revenue recognized within one year			1,000		1,000
Customer deposits			5,900		5,900
nstg_ReimbursementOfCounterpartyCosts			$ 300	$ 100	$ 400	$ 100
Number of warrants exercised | shares			0		0
Collaborative Arrangement | Lam Research Corporation | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of warrants, outstanding | shares		1,000,000
Revenue		$ 50,000