v3.6.0.2

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) | 12 Months Ended
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Dec. 31, 2014 USD ($) $ / shares
Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) |
Preferred stock (in dollars per share) | $ / shares | $ 12.76
Preferred stock issuance costs | $ | $ 86,933

X
- Definition Represents the numerator used when converting the convertible preferred stock to common stock. + References No definition available. + Details
Name: | ntra_ConvertiblePreferredStockConversionNumeratorPerShare
Namespace Prefix: | ntra_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents direct costs associated with issuing temporary equity. + References No definition available. + Details
Name: | ntra_TemporaryEquityIssuanceCosts
Namespace Prefix: | ntra_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_StatementOfStockholdersEquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration