Convertible Notes - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Sep. 08, 2014	Mar. 31, 2015	Sep. 08, 2014
Debt Instrument [Line Items]
Debt instrument, convertible, ownership cap in shares of common stock		9.985%
Convertible notes
Debt Instrument [Line Items]
Debt instrument, interest rate percentage		1.75%
Debt instrument, interest rate description		payable quarterly in arrears on the first business day of each January, April, July and October.
Debt instrument, maturity description		seventh anniversary from the date of issuance
Debt instrument, convertible, stock price trigger		$ 30
Debt instrument, convertible, threshold trading days		30 days
Debt instrument, convertible, terms of security		The Convertible Notes constitute a senior secured obligation of the Company, collateralized by a first priority security interest in substantially all of the assets of the Company. The Convertible Notes provide that, upon the request of the Company, Deerfield will release all of the liens on the collateral if both of the following occur: (i) beginning one month after U.S. Food and Drug Administration approval of either Rhopressa™ or Roclatan™, shares of the Company’s common stock have traded at a price above $30 per share (subject to adjustment for any subdivision or combination of outstanding common stock) for 30 consecutive trading days, and (ii) the Company is prepared to close a financing that will be secured by a lien on the Company’s assets, subject only to the release of the lien on the Company’s assets by Deerfield.
Debt instrument, transaction fee		$ 625,000
Reimbursed expenses incurred by Deerfield in connection with transaction		250,000
Legal and advisory fees		1,300,000
Debt instrument, convertible, ownership cap in shares of common stock		9.985%
Debt instrument, convertible, initial conversion price per share	$ 24.80		$ 24.80
Debt instrument, convertible, common stock conversion rate per $1,000 principal amount	40.32
Debt instrument, convertible, conversion premium percentage	30.00%		30.00%
Debt instrument, convertible, maximum increase to the initial conversion rate per $1,000 principal amount		12.07
Debt instrument, convertible, ownership percentage threshold necessary to declare principal and accrued interest payable and due in the event of default		50.00%
Unamortized debt discounts		813,000
Interest expense related to Convertible Notes		$ 539,000