v3.3.1.900

Consolidated Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013
E |  |
Preferred stock (in dollars per share) | $ 6.0199 | $ 6.02
Preferred stock issuance costs |  | $ 405,371
F |  |
Preferred stock (in dollars per share) | $ 12.7629 |
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
- Details
Name: | us-gaap_StatementClassOfStockAxis=ntra_SeriesEConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=ntra_SeriesFConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |