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Description of Business - Additional Information (Details)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Significant Accounting Policies [Line Items]    
Number of operating segments 1us-gaap_NumberOfOperatingSegments  
Sales Revenue, Net | Customer Concentration Risk | Customers Located Outside Of United States    
Significant Accounting Policies [Line Items]    
Sales revenue percentage 4.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= htgm_CustomersLocatedOutsideOfUnitedStatesMember
32.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_MajorCustomersAxis
= htgm_CustomersLocatedOutsideOfUnitedStatesMember