Subsequent Events - Additional Information (Detail) - USD ($)				1 Months Ended	3 Months Ended	12 Months Ended
	May 10, 2017	Apr. 28, 2017	Sep. 26, 2014	Apr. 26, 2017	Mar. 31, 2017	Dec. 31, 2016	Jan. 17, 2012
Subsequent Event [Line Items]
Facility fee payment			$ 75,000
Warrants expiration period			7 years
Loan and Security Agreement [Member]
Subsequent Event [Line Items]
Warrants to purchase common shares							430,815
Term loans issuance date					Jan. 17, 2012
Facility fee payment			$ 255,000
Lincoln Park Capital Fund, LLC [Member]
Subsequent Event [Line Items]
Gross proceeds					$ 5,304,000	$ 412,500
Subsequent Event [Member]
Subsequent Event [Line Items]
Warrants to purchase common shares		24,900,000
Public offering price		$ 1.00
Gross proceeds from public offering		$ 24,900,000
Net proceeds from public offering		$ 23,200,000
Warrants exercised		0
Subsequent Event [Member] | Loan and Security Agreement [Member] | Term Loan [Member]
Subsequent Event [Line Items]
Warrants expiration period	5 years
Subsequent Event [Member] | Loan and Security Agreement [Member] | Term Loan [Member] | First Tranche [Member]
Subsequent Event [Line Items]
Facility fee payment	$ 170,000
Warrants, exercise price	$ 1.00
Subsequent Event [Member] | Loan and Security Agreement [Member] | Term Loan [Member] | First Tranche [Member] | Maximum [Member]
Subsequent Event [Line Items]
Warrants to purchase common shares	1,244,746
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member]
Subsequent Event [Line Items]
Term loans issuance date	May 10, 2017
Term loans aggregate principal amount	$ 17,000,000
Interest only payment period	24 months
Term loans maturity period	4 years
Repayment of term loans period	2 years
Debt instrument amortization schedule	24 months
Debt instrument repayment term	The interest-only period will end if the Company fails to meet any Interest-Only Milestone. Commencing on the first day of the month following such failure to achieve an Interest-Only Milestone, the Company will be required to repay the term loans over a two year period, based on a twenty-four (24) month amortization schedule.
Interest-only milestone terms	The Interest-Only Milestones require the Company to (i) achieve certain twelve month revenue targets, measured quarterly, commencing with quarter ending March 31, 2018, (ii) meet a minimum capital raising threshold through the sale and issuance of equity securities during the period from April 10, 2017 through May 31, 2018 and (iii) obtain clearance for commercialization of the Senhance System by the U.S. Food and Drug Administration (“Senhance Clearance”) by May 30, 2018 (each such milestone, an “Interest-Only Milestone”).
Term loans fixed interest rate	11.00%
Term loans fixed interest rate, paid in-kind percentage	2.50%
Term loans payment terms	The Company will be required to repay the term loans if they are accelerated following an event of default. In addition, the Company is permitted to prepay the term loans in full at any time upon five (5) business days’ written notice to the Lenders. Upon the earliest to occur of the maturity date, acceleration of the term loan, or prepayment of the term loan, the Company is required to make a final payment equal to the total term loan commitment multiplied by four percent (4%) (the “Final Fee”); provided, however, that in the event the Company refinances its obligations with the Lender after Senhance Clearance, no Final Fee or Prepayment Fee (as defined below) will be due thereunder ; and provided, further, that if the Company elects to refinance its obligations prior to the funding of the second tranche, the Final Fee with respect to the second tranche shall be paid in full on the date of such refinancing. Any prepayment of the term loans in full, whether mandatory or voluntary, must include (i) the Final Fee, (ii) interest at the default rate (which is the rate otherwise applicable plus five percent (5%)) with respect to any amounts past due, (iii) the Lenders’ expenses and all other obligations that are due and payable to the Lenders and (iv) a prepayment fee of three percent (3%) if the term loan is paid in full on or before the first anniversary of the effective date, two percent (2%) if paid off after the first anniversary but on or before the second anniversary of the effective date and one percent (1%) if paid off after the second anniversary but on or before the third anniversary of the effective date (the “Prepayment Fee”).
Term loans prepayment written notice period	5 days
Multiplier percentage of term loan commitment final fee payment	4.00%
Percentage of additional interest rate added to default rate	5.00%
Debt instrument covenant terms	Under the terms of the Innovatus Loan Agreement, the Company is required to maintain minimum unrestricted cash in an amount equal to (x) six million dollars ($6,000,000), at all times prior to Senhance Clearance; and (y) at all times thereafter, the least of (i) $6,000,000, (ii) the Company’s trailing three (3) months’ cash used to fund operating activities, as determined as of the most recent month end and (iii) the then outstanding principal amount of the term loans, together with accrued but unpaid interest.
Minimum unrestricted cash requirement prior to clearance	$ 6,000,000
Covenants unrestricted cash requirement amount	$ 6,000,000
Covenant measurement trailing period for cash operating activities	3 months
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member] | On or Before First Anniversary of Effective Date [Member]
Subsequent Event [Line Items]
Prepayment fee percentage	3.00%
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member] | After First Anniversary but on or Before Second Anniversary of the Effective Date [Member]
Subsequent Event [Line Items]
Prepayment fee percentage	2.00%
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member] | After Second Anniversary but on or Before Third Anniversary of the Effective Date [Member]
Subsequent Event [Line Items]
Prepayment fee percentage	1.00%
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member] | First Tranche [Member]
Subsequent Event [Line Items]
Term loans aggregate principal amount	$ 14,000,000
Subsequent Event [Member] | Loan and Security Agreement [Member] | Innovatus Life Sciences Lending Fund I, LP [Member] | Term Loan [Member] | Second Tranche [Member]
Subsequent Event [Line Items]
Term loans aggregate principal amount	$ 3,000,000
Subsequent Event [Member] | Lincoln Park Capital Fund, LLC [Member]
Subsequent Event [Line Items]
Gross proceeds				$ 5,700,000
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Number of common stock or warrants in each unit		1
Subsequent Event [Member] | Common Stock [Member] | Series A Warrant [Member]
Subsequent Event [Line Items]
Number of common stock or warrants in each unit		1
Subsequent Event [Member] | Common Stock [Member] | Series B Warrant [Member]
Subsequent Event [Line Items]
Number of common stock or warrants in each unit		0.75