Reserve for Product Warranties - Additional Information (Detail)	3 Months Ended
Mar. 31, 2015
Product Warranties Disclosures [Abstract]
Product warranty accrual period	1 year

The period of accrual amount as of the balance sheet date of the aggregate extended product warranty liability is amortized.

No definition available.

Name:	nstg_ProductWarrantyAccrualPeriod
Namespace Prefix:	nstg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration