Collaboration Agreements - Additional Information (Detail)	1 Months Ended		3 Months Ended		6 Months Ended		7 Months Ended	12 Months Ended	34 Months Ended
	Aug. 31, 2017 USD ($) employee $ / shares shares	Mar. 31, 2014 USD ($)	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Estimated deferred revenue recognized within one year			$ 9,878,000		$ 9,878,000					$ 9,229,000
Collaborative Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement period					1 year
Collaborative Arrangement | Celgene Corporation
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and service revenue				$ 500,000	$ (200,000)	$ 600,000
Deferred revenue recorded under collaboration agreement			6,400,000		6,400,000
Estimated deferred revenue recognized within one year			5,200,000		5,200,000
Maximum success-based milestone payments		$ 21,500,000
Collaborative Arrangement | Celgene Corporation | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum success-based milestone payments		27,300,000
Collaborative Arrangement | Celgene Corporation | Upfront Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from collaborators								$ 6,000,000
Collaboration agreement upfront payment		$ 5,800,000							$ 2,100,000
Collaborative Arrangement | Merck Sharp & Dohme Corp.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and service revenue			500,000	4,500,000	1,400,000	6,600,000
Proceeds from collaborators			300,000	$ 1,500,000	900,000	3,300,000
Deferred revenue recorded under collaboration agreement			100,000		100,000
Collaborative Arrangement | Merck Sharp & Dohme Corp. | Upfront Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and service revenue						8,500,000
Proceeds from collaborators						$ 12,000,000	$ 3,900,000
Collaborative Arrangement | Lam Research Corporation
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and service revenue			4,000,000		8,200,000
Maximum amount of royalties payable (ratio)	3
Maximum number of employees | employee	10
Exercise price of warrants | $ / shares	$ 16.75
Issued warrants, value	$ 6,700,000
Proceeds from collaborators			7,900,000		11,400,000
Deferred revenue recorded under collaboration agreement			1,700,000		1,700,000
Estimated deferred revenue recognized within one year			800,000		800,000
Customer deposits			9,100,000		9,100,000
nstg_ReimbursementOfCounterpartyCosts			100,000		100,000
Amounts due for services provided			0		$ 0
Payments for services provided			$ 0
Number of warrants exercised | shares			0
Collaborative Arrangement | Lam Research Corporation | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and service revenue	$ 50,000,000
Number of warrants, outstanding | shares	1,000,000