Public Offerings - Additional Information (Detail) - USD ($) | Feb. 13, 2015 | Feb. 09, 2015 | Feb. 21, 2014 | Feb. 13, 2014 | Feb. 10, 2014 | Feb. 04, 2014 | Apr. 30, 2014 | Mar. 31, 2014 | Feb. 28, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014 |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Public offering, number of shares issued | | | | | | 1,900,000 | | | | | | |
Initial public offering, price per share | | | | | | $ 10 | | | | | | |
Net cash proceeds from issue of initial public offering after deducting underwriting discounts and additional costs | | | | | $ 17,400,000 | | | | | | | |
Increase in capital shares value | | $ 8,800,000 | | | | | | | | | | |
Additional costs incurred prior to, and associated with IPO, beginning of period | $ 200,000 | | | | $ 900,000 | | | | | | | |
Purchase of common stock by underwriters to cover overallotments, number of shares | 1,200,000 | | | | 285,000 | | | | | | | |
Purchase of common stock by underwriters to cover overallotments, per share | $ 1.25 | | | | $ 9.30 | | | | | | | |
Issuance of warrants to purchase shares of common stock | 1,200,000 | | | | | | | | | | | |
Exercise price of warrants | $ 1.56 | | | | | | | | | | | |
Overallotment issued to underwriter to purchase common stock, period | | 45 days | | | 45 days | | | | | 45 days | | |
Purchase of common stock by underwriters to cover overallotments, grant date fair value | | $ 7,690,395 | | | | | | | | $ 7,690,395 | | |
Warrants to purchase common stock, period | 5 years | | | | 5 years | | | | | 5 years | | |
Issuance of warrants to purchase shares of common stock, grant date fair value | | 1,627,396 | | | | | | | | $ 1,627,396 | | |
Series A Preferred Stock, shares converted to common stock | | | | | | 69,421,047 | | | | | | |
Preferred stock, par value | | | | | | $ 0.0001 | | | | | | |
Common stock, shares issued upon conversion of Series A Preferred Stock | | | | | | 1,652,851 | | | | | | |
Common stock, shares authorized | | | | | | 40,000,000 | | | | 40,000,000 | | 40,000,000 |
Preferred stock, shares authorized | | | | | | 5,000,000 | | | | | | |
Preferred stock, shares outstanding | | | | | | | | | | 0 | | 0 |
Preferred stock, shares issued | | | | | | | | | | 0 | | 0 |
Conversion price of notes | | | | | $ 10 | | | | | | | |
Shares of common stock vested as settlement of certain restricted stock units | | | | | 73,151 | | | | | | | |
Lock-up period | | | | | 180 days | | | | | | | |
Preferred warrants outstanding after cancellation of warrants due to early termination clauses | | | | | 1,587 | | | | | | | |
Warrants reclassified to additional paid-in capital | | | | | $ 2,500,000 | | | | | | | |
Unamortized discounts related to warrants | | | | | 1,000,000 | | | | | | | |
Underwriter IPO costs | | | | | 279,760 | | | | | | | |
Underwriter IPO discounts | | | | | 1,300,000 | | | | | | | |
Offering costs associated with IPO | | | | | 900,000 | | | | | | | |
Maximum amount of line of credit | | | | | | | | $ 2,600,000 | | | | |
Line of credit, outstanding balance repaid | | | | | 2,300,000 | | | | | | $ 2,346,000 | |
Line of credit, accrued interest paid | | | | | $ 27,043 | | | | | | | |
Payment of deferred salary obligations | | | | | | | $ 1,000,000 | $ 225,000 | $ 150,000 | | | |
Stock options granted | | | | | | | | | | 22,000 | | |
Repayment of laboratory equipment dues to supplier | | | | | | | | | | | | $ 70,000 |
Proceeds from issuance of common stock | $ 177,500 | | | | | | | | | $ 8,825,058 | $ 17,390,240 | |
Net proceeds from issuance of common stock | $ 9,100,000 | | | | | | | | | | | |
Common stock, par value | $ 0.0001 | | | | | | | | | $ 0.0001 | | $ 0.0001 |
Underwriter cost | | | | | | | | | | $ 200,000 | | |
Underwriting discounts | | | | | | | | | | 700,000 | | |
Non-underwriter costs | $ 300,000 | | | | | | | | | 300,000 | | |
Proceeds from exercise of common stock warrants | $ 9,700,000 | $ 9,700,000 | | | | | | | | 9,667,521 | | |
Aggregate increase in capital from public offerings | | | | | | | | | | $ 18,500,000 | | |
Employee [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Payment of additional deferred salary obligations | | | | | | | $ 344,883 | | | | | |
Director | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Public offering, number of shares issued | 142,000 | | | | | | | | | | | |
Issuance of warrants to purchase shares of common stock | | 142,000 | | | | | | | | | | |
2013 Equity Incentive Plan [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Common stock, shares authorized | | | | | | | | | | | | 1,426,051 |
Increase in number of shares of common stock covered by plan | | | | | 800,000 | | | | | | | |
Stock options granted | | | 54,298 | | | | | | | | | |
Option awards vesting period | | | | 3 years | | | | | | | | |
Option awards expiration period | | | | 10 years | | | | | | | | |
2013 Equity Incentive Plan [Member] | Director | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Stock options granted | | | | 238,500 | | | | | | | | |
2013 Equity Incentive Plan [Member] | Non Executive Chairman [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Stock options granted | | | | 53,108 | | | | | | | | |
2008 Convertible Note [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Debt, principal amount converted | | | | | $ 1,400,000 | | | | | | | |
Conversion price of notes | | | | | $ 10 | | | | | | | |
2013 Convertible Bridge Notes [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Exercise price of warrants | | | | | $ 10 | | | | | | | |
Debt, principal amount converted | | | | | $ 5,165,000 | | | | | | | |
Conversion price of notes | | | | | $ 10 | | | | | | | |
Convertible Note converted into preferred/common stock | | | | | 548,803 | | | | | | | |
Accrued interest on convertible debt converted | | | | | $ 313,017 | | | | | | | |
Warrants reclassified to additional paid-in capital | | | | | 258,249 | | | | | | | |
Line of Credit [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Exercise price of warrants | | | | | $ 10 | | | | | | | |
Warrants reclassified to additional paid-in capital | | | | | 128,903 | | | | | | | |
Collateral amount provided to secure Line of Credit | | | | | $ 2,600,000 | | | | | | | |
Convertible Bridge Notes And Line Of Credit [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Exercise price of warrants | | | | | $ 10 | | | | | | | |
Warrants reclassified to additional paid-in capital | | | | | 387,152 | | | | | | | |
Warrants reclassified to additional paid-in capital | | | | | $ 2,475,620 | | | | | | | |
Accrued interest [Member] | 2008 Convertible Note [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Accrued interest on convertible debt converted | | | | | 233,982 | | | | | | | |
Accrued interest [Member] | 2013 Convertible Bridge Notes [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Accrued interest on convertible debt converted | | | | | $ 300,000 | | | | | | | |
Aegis Capital Corp | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Issuance of warrants to purchase shares of common stock | 8,000,000 | | | | 95,000 | | | | | | | |
Exercise price of warrants | | | | | $ 12.50 | | | | | | | |
Purchase of common stock by underwriters to cover overallotments, grant date fair value | | | | | $ 202,143 | | | | | | | |
Issuance of warrants to purchase shares of common stock, grant date fair value | | | | | 544,116 | | | | | | | |
Aegis and Feltl [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Public offering, number of shares issued | 8,000,000 | | | | | | | | | | | |
Issuance of warrants to purchase shares of common stock | | 8,000,000 | | | | | | | | | | |
Offering, price per share | | $ 1.25 | | | | | | | | | | |
Common Stock [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Increase in capital shares value | | | | | $ 16,500,000 | | | | | | | |
Common Stock [Member] | 2008 Convertible Note [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Convertible Note converted into preferred/common stock | | | | | 163,399 | | | | | | | |
Common Stock [Member] | 2013 Convertible Bridge Notes [Member] | | | | | | | | | | | | |
Class Of Stock [Line Items] | | | | | | | | | | | | |
Convertible Note converted into preferred/common stock | | | | | 547,794 | | | | | | | |