Service agreement termination description

In February 2018, the Company terminated its relationship with a vendor who had been issued warrants to acquire 950,000 shares of Common Stock (the “Service Warrants”) with staggered vesting requirements. As part of the termination agreement, the Company accelerated the full vesting of the Service Warrants.

7 years

Class of Warrant or Right [Line Items]

Warrants - Additional Information (Detail) - shares		6 Months Ended
Warrants - Additional Information (Detail) - shares	Sep. 26, 2014	Jun. 30, 2018	Apr. 28, 2017	Jan. 17, 2012
Class of Warrant or Right [Line Items]
Service agreement termination description		In February 2018, the Company terminated its relationship with a vendor who had been issued warrants to acquire 950,000 shares of Common Stock (the “Service Warrants”) with staggered vesting requirements. As part of the termination agreement, the Company accelerated the full vesting of the Service Warrants.
Issue of warrants to purchase shares of company's common stock			24,900,000
Warrant expiration period	7 years
Loan and Security Agreement [Member]
Class of Warrant or Right [Line Items]
Issue of warrants to purchase shares of company's common stock				430,815