In April 2006, the Company’s Board of Directors (the “Board”) adopted and the stockholders approved the 2006 Stock Option Plan (“2006 Plan”), which provided for the grant of incentive and non-statutory stock options. In February 2013 the Board adopted and the stockholders approved the 2013 Equity Incentive Plan (“2013 Plan”), which became effective on March 21, 2013. At that time, the Company ceased to grant equity awards under the 2006 Plan. Under the 2013 Plan, 643 shares of common stock were originally reserved for issuance. Additionally, all reserved and unissued shares under the 2006 Plan are eligible for issuance under the 2013 Plan. The 2013 Plan authorizes the award of incentive and non-statutory stock options, restricted stock awards, stock appreciation rights, restricted stock units (“RSUs”), performance awards and stock bonuses to the Company’s employees, directors, consultants, independent contractors and advisors. On January 1 of each calendar year through 2023, the number of shares of common stock reserved under the 2013 Plan will automatically increase by an amount equal to 5% of the total outstanding shares as of the immediately preceding December 31, or such lesser number of shares as determined by the Board. Pursuant to terms of the 2013 Plan, the shares available for issuance increased by 297 shares of common stock on January 1, 2019. As of September 30, 2019, 708 shares of common stock were available for future grants under the 2013 Plan.

A summary of stock option activity under the 2006 Plan and 2013 Plan is as follows:

	Options Outstanding
	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (in Years)		Aggregate Intrinsic Value
Balances at December 31, 2018		436		$	29.01		6.79	$	—
Options granted		128			4.00		9.62		—
Options forfeited and cancelled		(14	)		62.96		—		—
Balances at September 30, 2019		550			22.33		6.95		—
Options exercisable		356			31.09		5.80		—
Options vested		356			31.09		5.80		—
Options vested and expected to vest		527			23.04		6.85		—

	RSUs Outstanding
	Number of Shares			Weighted Average Grant Date Fair Value Per Unit
Granted and unvested at December 31, 2018		834		$	7.99
RSUs granted		737			3.93
RSUs vested		(92	)		9.43
RSUs cancelled and withheld to cover taxes		(366	)		6.88
Granted and unvested at September 30, 2019		1,113		$	5.54

In February 2013, the Board and stockholders approved the 2013 Employee Stock Purchase Plan (“2013 ESPP”), under which 143 shares of common stock were originally reserved for issuance. The 2013 ESPP became effective on March 22, 2013. The 2013 ESPP generally provides for purchase periods each nine months with the purchase price for shares of common stock purchased under the 2013 ESPP is 85% of the lesser of the fair market value of the common stock on (1) the first trading day of the applicable offering period and (2) the last trading day of each purchase period in the applicable offering period. On January 1 of each calendar year following the first offering date, the number of shares reserved under the 2013 ESPP automatically increases by an amount equal to 1% of the total outstanding shares as of immediately preceding December 31, but not to exceed 100 shares. Pursuant to terms of the 2013 ESPP, the shares available for issuance increased by 59 shares on January 1, 2019. As of September 30, 2019, 171 shares were reserved for issuance under the 2013 ESPP. During the three and nine months ended September 30, 2019, zero and 42 shares, respectively, were issued under the 2013 ESPP. During the three and nine months ended September 30, 2018, zero and 31 shares, respectively, were issued under the 2013 ESPP.